Here is article from 8.dan ZNKR iaido hanshi teacher Eura Kazunori. He tried to attend 3 days zazen practice in shrine. He writes about this experience.
Zen Meditation Experience
By Eura Kazunori
Iaido Hanshi 8-dan
President of the Hachiōji Iaido Association, Tokyo
Translation by Stephen Robert Nagy
From Kendo-World magazine (Volume 3.1).
http://aishinkai.com/uploads/zen-meditation-experience1.pdf
Zen Meditation Experience
By Eura Kazunori
Iaido Hanshi 8-dan
President of the Hachiōji Iaido Association, Tokyo
Translation by Stephen Robert Nagy
From Kendo-World magazine (Volume 3.1).
http://aishinkai.com/uploads/zen-meditation-experience1.pdf