How useful is uchikomi?

I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

I think if done properly it is useful, done badly - not so useful.

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

It seems to me that logically any question that starts with "has/is anyone" probably has at least one and probably more positive returns, if not on the current 7 billion people, then at least one all the people who have ever lived. If not, the stakes would be pretty high if there wasn't one than 1 on >10,000,000,000. The one exception probably is the question that ends on "... returned from the dead"

For the rest, it's very much like jkw says. Unfortunately so many people today seem to think of uchi-komi as some aerobic cardio exercise, dunno why. If cardio is what you wanna do, go running, go swimming go, practice on a rowing ergometer of stairmaster, use uchi-komi for what it is designed for.

I suppose I began with "I wonder if anyone....." because I felt awkward about the fact that I have some doubts about it.

It seems to me less helpful in the beginning when the technique is not established. I tend to feel it would be better then to do throwing practise.

Also like youself I have seen it used as a fitness exercise (or that is what it has become). This seems to be less helpful and maybe harmful (for the technique).

samsmith2424 wrote:I suppose I began with "I wonder if anyone....." because I felt awkward about the fact that I have some doubts about it.

It seems to me less helpful in the beginning when the technique is not established. I tend to feel it would be better then to do throwing practise.

Also like youself I have seen it used as a fitness exercise (or that is what it has become). This seems to be less helpful and maybe harmful (for the technique).

Here is an older thread about uchi komi which has some useful perspectives, although doesn't touch on teaching beginners.

https://judo.forumotion.com/t499-uchi-komi-training

samsmith2424 wrote:

It seems to me less helpful in the beginning when the technique is not established. I tend to feel it would be better then to do throwing practise.

problem with that is that it sucks to take a fall from unestablished technique. Further, you really wouldn't want to put a noob as uke if you're going through to kake.

uchikomi has it's uses, not the least of which is to prevent noobs from dumping people on their heads, preventing noobs from harming their partners. I mean, how many of us have been glad that a person learning tai otoshi wasn't actually going through to kake when they're just figuring out where their leg goes in relationship to your knee? And that's merely tai otoshi - an obvious example of why uchi komi to establish technique is essential.

Stacey wrote:

samsmith2424 wrote:

It seems to me less helpful in the beginning when the technique is not established. I tend to feel it would be better then to do throwing practise.

problem with that is that it sucks to take a fall from unestablished technique.  Further, you really wouldn't want to put a noob as uke if you're going through to kake.

uchikomi has it's uses, not the least of which is to prevent noobs from dumping people on their heads, preventing noobs from harming their partners.  I mean, how many of us have been glad that a person learning tai otoshi wasn't actually going through to kake when they're just figuring out where their leg goes in relationship to your knee?  And that's merely tai otoshi - an obvious example of why uchi komi to establish technique is essential.

I don't feel happy with uchikomi used in that way. For one reason there is very little feed back for tori as to how successful his throw would be. Furthermore you may be forming a technique which actually doesn't work well. Also, so what if a few people take a few hard falls. If safety is an issue put the beginners on with experienced people who can take the falls and also give some feed back.

For me giving beginners uchikomi seems a real waste of time and poor teaching practise.

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

Disclaimer- I am a kyu-grade student of Judo with only a few years of experience and do not write with any particular authority, merely interest and my own observations.

This matter is something I've been mulling over for a while.

I suspect that issues associated with usefulness have less to do with the exercise itself than how it is used as a didactic tool. Uchikomi can be immensely useful for working with beginners and avoiding injury to them or their partners, building up speed, developing control, isolating and refining particular aspects of a throw, generally doing this whilst preserving ones training partners, and so on; but like anything there seems to be a distinct possibility for it to be practiced in a context and way that can potentially be ultimately detrimental.

The issues associated with practicing a movement that should by necessity be smooth and continuous from initiation to execution, by repetitively and deliberately stopping half way through are probably self-explanatory, analogous to only point-sparring in striking arts and expecting to be able to deliver a genuinely damaging blow when you need to. My 2c of personal experience is that for a fairly significant period of time (over half my total time in Judo thus far) the club I trained at very scarcely practiced nagekomi. This is understandable given that it was and is a small recreational club with very limited mat space and at the time what were apparently (though I had no basis for comparison) ancient and exceptionally hard mats. But- and of course there are far too many potential influencing factors for me to write this with much certainty, but I suspect- I suspect that the hiccup I found in my throws between the tsukuri and the kake, simply because the automatic follow through wasn't there, is not unrelated to practicing them predominantly in this way by such a significant margin. Then again, as a qualifier, I also have just about no natural aptitude for Judo or tendency towards athleticism in general, so perhaps to most this would simply not be a problem. Anyhow, are your reservations regarding uchikomi at all similar?

Warm regards.

samsmith2424 wrote:


I don't feel happy with uchikomi used in that way. For one reason there is very little feed back for tori as to how successful his throw would be. Furthermore you may be forming a technique which actually doesn't work well. Also, so what if a few people take a few hard falls. If safety is an issue put the beginners on with experienced people who can take the falls and also give some feed back.

For me giving beginners uchikomi seems a real waste of time and poor teaching practise.

Sorry, but no experienced judoka is going to let a noob try out tai otoshi to kake until that noob can establish that they know exactly where their leg is going to go in relationship to the experienced judoka's knee. There's just no reason to risk suffering that kind of injury by allowing a noob to practice through kake when s/he has no idea where his/her partner's knee is.

Experienced judoka can only avoid so many injuries. Asking them to take a ton of extra risk while a noob learns body position by execution is a quick way to make sure you have nobody on the tatami except noob students. It's not just landing that's problematic - it's the fitting in that can cause problems. As stated, getting your knee locked out in a tai otoshi uchi komi with somebody learning is hard enough on a body; getting your knee ripped apart is unacceptable. There are a myriad of throws where landing isn't the most difficult, injury prone aspect of the throw. Best to learn body position and how the proper position feels well before you try to kake. Further, if you're not engaged in an exploration of kuzushi to establish your partner's body position for the fit-in, then you're really not even bothering to try to learn anything from uchi komi practice.

samsmith2424 wrote:

For me giving beginners uchikomi seems a real waste of time and poor teaching practise.

Yosemite Sam,

What you say is only true if you narrow the purpose of uchikomi to something useful for learning the technical details of throws ... pull here, step there, bend there, twist here, shout here ...

If you take a peek at the very, very revealing interview with Shioda and Kimura that Chris Li put up in the documentary and history section you can get a glimpse of the common source of the prescription of uchikomi as the cure for all ills in judo tradition.  That is ... self mortification ... in a variety peculiar to Japan.  Not unique in overall concept ... Paul for example wrote "For if you live after the flesh, you shall die: but if you through the Spirit do put to death the deeds of the body, you shall live."

From the interview Kimura says "No, after I went home and ate I would take a bath and then do solo training. First, a thousand push-ups, then body-building – six-hundred bench presses with 80 kg (175 lbs) barbells. Just that would take about an hour. Then uchikomi (打ち込み) against a maple tree a thousand times (emphasis by Bill C). I would wrap a Judo belt around a very thick maple tree and do uchikomi, but doing that a thousand times a day the trees would snap rather quickly."

You can't get around judo very long without running across the concept that destroying the body somehow frees "the spirit" to do things that the body cannot.  Sometimes Western instructors ... typically passing along a watered-down and misunderstood version of Japanese training will come up with an explanation like "well, after your muscles are tired there is nothing left but technique ..." though most of the time uchikomi is prescribed simply because "that's the way we've always done it" combined with a healthy dose of unquestioned hierarchy.

The example that comes to mind which sums up this tendency well ... I have a friend ... well known to some on this forum ... who was struggling with European style kumikata during college competition in Japan ... his instructor's answer?  Hundreds of uchikomi.  Truth was the instructor probably didn't have a ghost of a clue how to deal with a strong overhand grip ... or even if he did the answer to every question must be to see how much the student can take without breaking and certainly by doing uchikomi until he dropped his spirit would soar and he would be dropping in turn all those oafish gaijin with real Japanese judo ... perseverance, in that view, has a beauty that supersedes even victory itself.

Stacey wrote:

samsmith2424 wrote:


I don't feel happy with uchikomi used in that way. For one reason there is very little feed back for tori as to how successful his throw would be. Furthermore you may be forming a technique which actually doesn't work well. Also, so what if a few people take a few hard falls. If safety is an issue put the beginners on with experienced people who can take the falls and also give some feed back.

For me giving beginners uchikomi seems a real waste of time and poor teaching practise.

Sorry, but no experienced judoka is going to let a noob try out tai otoshi to kake until that noob can establish that they know exactly where their leg is going to go in relationship to the experienced judoka's knee.  There's just no reason to risk suffering that kind of injury by allowing a noob to practice through kake when s/he has no idea where his/her partner's knee is.

Experienced judoka can only avoid so many injuries.  Asking them to take a ton of extra risk while a noob learns body position by execution is a quick way to make sure you have nobody on the tatami except noob students.  It's not just landing that's problematic - it's the fitting in that can cause problems.  As stated, getting your knee locked out in a tai otoshi uchi komi with somebody learning is hard enough on a body; getting your knee ripped apart is unacceptable.  There are a myriad of throws where landing isn't the most difficult, injury prone aspect of the throw.  Best to learn body position and how the proper position feels well before you try to kake.  Further, if you're not engaged in an exploration of kuzushi to establish your partner's body position for the fit-in, then you're really not even bothering to try to learn anything from uchi komi practice.

+1

From someone whose knee was ruined by an awful taiotoshi 12 months ago. Surgery, physio, still f****d, competitive judo finished in the blink of an eye.

I've always considered uchikomi like doing scales on a musical instrument. When I wanted to be able to do improvisation on the guitar, practicing scales, arpeggios, and other exercises developed muscle memory and fluidity. Playing a scale as rapidly as possible over and over again isn't music, though.

When I practice uchikomi, I approach it like I did with guitar scales. I begin slowly and focus on getting the form perfect right up to the point of kake. I gradually increase the speed, monitoring accuracy along the way. If I start to make mistakes, I slow down and work on the form. When I'm consistently hitting correct position and approaching actual speed, I'll see if uke is ready and move into nagekomi.

Doing this helps improve things like proper foot placement, hip placement, etc. without having to make uke hit the ground every time. I've seen guys do some really fast uchikomi, but for the most part, those are guys whose technique is so good, they're hitting the proper position 99 percent of the time. Since my club only gets to practice one day a week, uchikomi is essential to my progress. I use the "belt around a pole" method since I don't always have an uke handy.

Cichorei Kano wrote:

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

It seems to me that logically any question that starts with "has/is anyone" probably has at least one and probably more positive returns, if not on the current 7 billion people, then at least one all the people who have ever lived. If not, the stakes would be pretty high if there wasn't one than 1 on >10,000,000,000. The one exception probably is the question that ends on "... returned from the dead"

For the rest, it's very much like jkw says. Unfortunately so many people today seem to think of uchi-komi as some aerobic cardio exercise, dunno why. If cardio is what you wanna do, go running, go swimming go, practice on a rowing ergometer of stairmaster, use uchi-komi for what it is designed for.

Who "designed" uchi komi, when and why ? When did it become such a integral part of judo training ?

I get that uchikomi is basically a kind of part-part-whole training method. Maybe just the Japanese version of it specialized to Judo or ju jutsu ?

I've often speculated to myself that in the early days of Judo, what with the (I assume) lack of suspended floors and the antique tatami, uchikomi were necessary.

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

Doing uchikomi "correctly" is often more difficult than doing the complete technique correctly. Stopping a dynamic movement in the act just before the "point of no return" is hard as hell, requiring a LOT of coordination and control. That is my primary problem with uchikomi as a training method.

The part-part-whole training method is legit, of course. In the case of judo nage waza, though, it leaves a lot to be desired as most often applied.

Not useless, but overused in my opinion.

Stacey wrote:

samsmith2424 wrote:


I don't feel happy with uchikomi used in that way. For one reason there is very little feed back for tori as to how successful his throw would be. Furthermore you may be forming a technique which actually doesn't work well. Also, so what if a few people take a few hard falls. If safety is an issue put the beginners on with experienced people who can take the falls and also give some feed back.

For me giving beginners uchikomi seems a real waste of time and poor teaching practise.

Sorry, but no experienced judoka is going to let a noob try out tai otoshi to kake until that noob can establish that they know exactly where their leg is going to go in relationship to the experienced judoka's knee.  There's just no reason to risk suffering that kind of injury by allowing a noob to practice through kake when s/he has no idea where his/her partner's knee is.

Experienced judoka can only avoid so many injuries.  Asking them to take a ton of extra risk while a noob learns body position by execution is a quick way to make sure you have nobody on the tatami except noob students.  It's not just landing that's problematic - it's the fitting in that can cause problems.  As stated, getting your knee locked out in a tai otoshi uchi komi with somebody learning is hard enough on a body; getting your knee ripped apart is unacceptable.  There are a myriad of throws where landing isn't the most difficult, injury prone aspect of the throw.  Best to learn body position and how the proper position feels well before you try to kake.  Further, if you're not engaged in an exploration of kuzushi to establish your partner's body position for the fit-in, then you're really not even bothering to try to learn anything from uchi komi practice.

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

Ben Reinhardt wrote:

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

Noob to the throw. Tai otoshi isn't the first throw usually taught. I don't know where your governing body puts it in the curriculum, but it's usually up there with harai ogoshi as one of the first forward throws taught where the legs aren't inside the legs of uke. Whatever. The killer for this throw is that if you don't know where your partner's knee is, and you don't work on the dynamics of the throw, you're going to lock it out and if you kake when you do, you are going to damage your partner. Sure, you can teach it so that the stretched out leg is resting on the ground, and chances are you're not going to have problems locking your partner's leg out, but that's not horribly practical. What you are trying to do with uchi komi is get kuzushi and body position, and get it so you know it and minimize your chances of damaging your partner while increasing the chances of actually throwing him/her. Accidents will happen, but good uchi komi progressing to moving, to kake, then into randori can seriously diminish injury.

Ben Reinhardt wrote:

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

You know the answer to that ... at least the first one. New, adventurous students see it and try to copy. They peruse that old, excellent piece of artwork by Bill Nauta and proceed to pose that way. Or they simply are trying seoinage and still have their feet three miles apart as beginners commonly do.

As a result ... I suggest that one should teach early and often. But correctly and under proper supervision. With control. And a teaching method that insures control.

Sorry to say, but there are plenty of instructors out there that never learned taiotoshi properly themselves. There are the I am going to muscle you over and trip you with my leg guys, the over the top and on the head (tori and uke) guys, the hip throw with a superwide stance guys ... hell, one of your famous national judo organizations just awarded a tender-age rokudan to one of the more notorious local perpetrators ... who teaches the most dangerous of these to 5 year olds.

Then on top of that ... there are a long list of correct ways ... and I mean correct with no quote marks ... to perform taiotoshi. Do you agree Sir Ben? And nice to hear from you by the way.

Ben Reinhardt wrote:

Cichorei Kano wrote:

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

It seems to me that logically any question that starts with "has/is anyone" probably has at least one and probably more positive returns, if not on the current 7 billion people, then at least one all the people who have ever lived. If not, the stakes would be pretty high if there wasn't one than 1 on >10,000,000,000. The one exception probably is the question that ends on "... returned from the dead"

For the rest, it's very much like jkw says. Unfortunately so many people today seem to think of uchi-komi as some aerobic cardio exercise, dunno why. If cardio is what you wanna do, go running, go swimming go, practice on a rowing ergometer of stairmaster, use uchi-komi for what it is designed for.

Who "designed" uchi komi, when and why ? When did it become such a integral part of judo training ?

I get that uchikomi is basically a kind of part-part-whole training method. Maybe just the Japanese version of it specialized to Judo or ju jutsu ?

I've often speculated to myself that in the early days of Judo, what with the (I assume) lack of suspended floors and the antique tatami, uchikomi were necessary.

Repetitive exercises exist in many Japanese martial arts; kendô has its suburi (repetitive up and down swinging of the shinai), whereas sumô has its butsu-kari (which is from where jûdô adopted it).

I also note that there exist numerous forms to training, but with the exception of uchi-komi, nage-komi, randori, ytandoku-renshû, aku-soku-geiko, and kakari-geiko these other forms are not commonly known among Western jûdô practitioners.

samsmith2424 wrote:I suppose I began with "I wonder if anyone....." because I felt awkward about the fact that I have some doubts about it.

It seems to me less helpful in the beginning when the technique is not established. I tend to feel it would be better then to do throwing practise.

Also like youself I have seen it used as a fitness exercise (or that is what it has become). This seems to be less helpful and maybe harmful (for the technique).

I tend to agree, Sam. There are also perhaps more important things in learning to throw a resisting opponent than not throwing !

Cichorei Kano wrote:

Ben Reinhardt wrote:

Cichorei Kano wrote:

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

It seems to me that logically any question that starts with "has/is anyone" probably has at least one and probably more positive returns, if not on the current 7 billion people, then at least one all the people who have ever lived. If not, the stakes would be pretty high if there wasn't one than 1 on >10,000,000,000. The one exception probably is the question that ends on "... returned from the dead"

For the rest, it's very much like jkw says. Unfortunately so many people today seem to think of uchi-komi as some aerobic cardio exercise, dunno why. If cardio is what you wanna do, go running, go swimming go, practice on a rowing ergometer of stairmaster, use uchi-komi for what it is designed for.

Who "designed" uchi komi, when and why ? When did it become such a integral part of judo training ?

I get that uchikomi is basically a kind of part-part-whole training method. Maybe just the Japanese version of it specialized to Judo or ju jutsu ?

I've often speculated to myself that in the early days of Judo, what with the (I assume) lack of suspended floors and the antique tatami, uchikomi were necessary.

Repetitive exercises exist in many Japanese martial arts; kendô has its suburi (repetitive up and down swinging of the shinai), whereas sumô has its butsu-kari (which is from where jûdô adopted it).

I also note that there exist numerous forms to training, but with the exception of uchi-komi, nage-komi, randori, ytandoku-renshû, aku-soku-geiko, and kakari-geiko these other forms are not commonly known among Western jûdô practitioners.

Thank you for the response. Been wondering that for decades.

I am familiar with all the other forms of training you listed. I did come across another term for tandoku renshu in Nobuyuki Sato book on ashi waza (published by ippon books),but I can't remember what it is.

BillC wrote:

Ben Reinhardt wrote:

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

You know the answer to that ... at least the first one.  New, adventurous students see it and try to copy.  They peruse that old, excellent piece of artwork by Bill Nauta and proceed to pose that way.  Or they simply are trying seoinage and still have their feet three miles apart as beginners commonly do.

As a result ... I suggest that one should teach early and often.  But correctly and under proper supervision.  With control.  And a teaching method that insures control.

Sorry to say, but there are plenty of instructors out there that never learned taiotoshi properly themselves.  There are the I am going to muscle you over and trip you with my leg guys, the over the top and on the head (tori and uke) guys, the hip throw with a superwide stance guys ... hell, one of your famous national judo organizations just awarded a tender-age rokudan to one of the more notorious local perpetrators ... who teaches the most dangerous of these to 5 year olds.

Then on top of that ... there are a long list of correct ways ... and I mean correct with no quote marks ... to perform taiotoshi.  Do you agree Sir Ben?  And nice to hear from you by the way.

LOL at first answer to that...I tell my students nobody tries anything unless they've been instructed. But I only instruct in small groups where I can watch and "control" everything that goes on.

Sorry, but I won't teach Tai Otoshi early and often. It is a bit of a chicken and egg question. I agree that it can be done by a competent instructor who uses a careful progression, BUT, I find that focusing on "both feet on ground" throws, other than Ouchi Gari, Kouchi Gari, and De Ashi Barai gets results quicker. By results I mean the student is having success faster.

Tender-age rokudan, what else is new. Tender age or not how many people really deserve rokudan. OT for worth a comment, eh?

I agree there are many correct ways to do Tai Otoshi, being it is a principle. I think most of us could agree on a fairly standardized version. Many paths to the truth though...



I can do Tai Otoshi relatively well, but it is not one of my former high percentage throws in randori or competition.

Stacey wrote:

Ben Reinhardt wrote:

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

Noob to the throw.  Tai otoshi isn't the first throw usually taught. I don't know where your governing body puts it in the curriculum, but it's usually up there with harai ogoshi as one of the first forward throws taught where the legs aren't inside the legs of uke.  Whatever.  The killer for this throw is that if you don't know where your partner's knee is, and you don't work on the dynamics of the throw, you're going to lock it out and if you kake when you do, you are going to damage your partner.  Sure, you can teach it so that the stretched out leg is resting on the ground, and chances are you're not going to have problems locking your partner's leg out, but that's not horribly practical.  What you are trying to do with uchi komi is get kuzushi and body position, and get it so you know it and minimize your chances of damaging your partner while increasing the chances of actually throwing him/her.  Accidents will happen, but good uchi komi progressing to moving, to kake, then into randori can seriously diminish injury.

My personal governing body puts it in the curriculum when the student has enough coordination and base skill/control to begin learning it. That varies from student to student. Once size fits all throw lists I avoid.

In any case, no issue with using uchi komi as a teaching tool as part of a safe and effective skill progression.

Quicksilver wrote:

samsmith2424 wrote:I wonder if anyone has any doubts about the usefulness of uchikomi. If so why?

Disclaimer- I am a kyu-grade student of Judo with only a few years of experience and do not write with any particular authority, merely interest and my own observations.

This matter is something I've been mulling over for a while.

I suspect that issues associated with usefulness have less to do with the exercise itself than how it is used as a didactic tool. Uchikomi can be immensely useful for working with beginners and avoiding injury to them or their partners, building up speed, developing control, isolating and refining particular aspects of a throw, generally doing this whilst preserving ones training partners, and so on; but like anything there seems to be a distinct possibility for it to be practiced in a context and way that can potentially be ultimately detrimental.

The issues associated with practicing a movement that should by necessity be smooth and continuous from initiation to execution, by repetitively and deliberately stopping half way through are probably self-explanatory, analogous to only point-sparring in striking arts and expecting to be able to deliver a genuinely damaging blow when you need to. My 2c of personal experience is that for a fairly significant period of time (over half my total time in Judo thus far) the club I trained at very scarcely practiced nagekomi. This is understandable given that it was and is a small recreational club with very limited mat space and at the time what were apparently (though I had no basis for comparison) ancient and exceptionally hard mats. But- and of course there are far too many potential influencing factors for me to write this with much certainty, but I suspect- I suspect that the hiccup I found in my throws between the tsukuri and the kake, simply because the automatic follow through wasn't there, is not unrelated to practicing them predominantly in this way by such a significant margin. Then again, as a qualifier, I also have just about no natural aptitude for Judo or tendency towards athleticism in general, so perhaps to most this would simply not be a problem. Anyhow, are your reservations regarding uchikomi at all similar?

Warm regards.

Your observations and comments are right on.

It's common sense and I believe an established fact of learning that it is best to do a complete version of a movement being learned as soon as safely practicable, and under as close as possible conditions to which the actual movement will be done (for example, competition).

All that needs to be done in safely progressive way. Skill progression is the term. Sometimes the skills you teach/practice may not be directly part of the actual "technique", but related to physical deficits in the student. It's ideal to combine that sort of practice with something similar to the technique being taught, but that is still close to a complete skill, or resembles the complete skill.

An example would be "throwing" uke with uke starting on one or both knees, and tori standing. This is useful when students are not quite ready ukemi-wise to take normal speed/force falls and need to work on control issues in controlling uke. And following on into say, osaekomi waza as well.

In that case, you have a grip, a "throw", and transition to a pin. It is done statically, but is basically a facsimile of the complete skill as it would be done in randori or shiai. As uke and tori get better and better, you progress as dictated by the particular technique/skill in question.

Stacey wrote:

Ben Reinhardt wrote:

Begs the question, why teach noobs Tai Otoshi? How noobish are we talking here?

Noob to the throw.  Tai otoshi isn't the first throw usually taught. I don't know where your governing body puts it in the curriculum, but it's usually up there with harai ogoshi as one of the first forward throws taught where the legs aren't inside the legs of uke.  Whatever.  The killer for this throw is that if you don't know where your partner's knee is, and you don't work on the dynamics of the throw, you're going to lock it out and if you kake when you do, you are going to damage your partner.  Sure, you can teach it so that the stretched out leg is resting on the ground, and chances are you're not going to have problems locking your partner's leg out, but that's not horribly practical.  What you are trying to do with uchi komi is get kuzushi and body position, and get it so you know it and minimize your chances of damaging your partner while increasing the chances of actually throwing him/her.  Accidents will happen, but good uchi komi progressing to moving, to kake, then into randori can seriously diminish injury.

Jûdô isn't always taught according to a proper curriculum. At my first club I never did jûdô in a kids division because there wasn't one. Our club was too small each work-out was for everyone. So as a kid, I also started judo practice from day one regularly working with adults. Although they assigned someone to teach me ukemi, and then the classical de-ashi-barai, hiza-guruma thing, for many newbies these throws appear 'fake'. The coordination for de-ashi-barai exceeds the level of a beginner, and hiza-guruma is not exactly a throw you see being done frequently with success. The situation with ô-goshi etc, for a newbie are simple: they too are fake throws because you can of course not get passed uke's arms. I got taught tai-otoshi maybe as the 5th throw or so and it worked and liked it because all you want as a white belt is getting your opponent on the ground. That is what judo is all about, you think at that level. I also remember we were once with a group of kids monkeying around when I had that age, and someone grabbed me from behind, and I could not get out of it, but I then applied tai-otoshi and he went over flat on his back. In other words, one reason why a white belt might do such a throw, is because he might find it the only throw that 'works'. Of course, in reality the coordination of a proper tai-otoshi is far more difficult than of some of the other throws, but that the beginner's level one's view is biased. I think of my tai-otoshi then as an awesome throw since I was throwing people with it far more senior than me. That's my recollection. if there would have existed any film recordings from then, and if I would now watch it, I would probably conclude that my tai-otoshi was awful full of mistakes, due to the difference in judgement between me then and now.

But what I wanted to say, is that as a beginner you don't get everywhere taught a "beginner's curriculum". Sometimes you just step in and go along with the flow hence being exposed to techniques which are not at all on a 6th or 5th kyû curriculum.

I teach tai otoshi as the first throw in my kids' class, for the very reason CK talked of - it gets kids in the game quickly. This works because my goal for kids is enjoyment over technical excellence (the latter being more my focus with youths). I've never experienced a leg injury doing so but I concentrate early on in throwing uke "off" tori, rather than winding their weight "on", as I see in so many other beginners.

One advantage of uchikomi that I would like to point out, is its good use of time. One can perform three or four uchikomi to every one nagekomi.