Shojin Ryori (Shojin means "devotion", Ryori means "cuisine") is a kind of vegetarian cuisine mainly for the believers of Buddhism. Wiki said "Rebirth is one basic tenet of Buddhism, and this includes rebirth of humans as other animals, and vice-versa. Due to the understanding of animals as conscious and suffering beings, many Buddhists do not kill animals and many also do not eat meat."
I was asking about Shojin Ryori from my foreign friend recently, but I didn't know about it so much. Actually I have very poor knowledge about Buddhism. Like I wrote before, I, my family and many of the people around me are not devout Buddhists. Not only for Buddhism, Japanese religious feelings seem to be unique. Actually, my Swedish friend went to a temple for ascetic training and he gave me a Shojin Ryori restaurant guide. I think he knew much better than I about Buddhism and Shojin Ryori. I checked about Shojin Ryori a little today, so I will leave the links here in my post.
>When Buddhism came to Japan from China, such vegetarian cuisine came together. But Shojin Ryori developed after the Kamakura period because of an influx of Zen. Rinzai and Soto are two big schools of Zen in Japan. Dogen is founder of the Soto Zen sect. He went to China to study Buddhism and learned about every daily life, including cooking and eating as a practice of Buddhism. He wrote "Tenzen Kyokun" and "Fushuku Hanpo" These books would be a kind of text book of Zen Buddhism.
In Shojin Ryori, soy beans are a very important protein source. But it's impossible to eat raw soy beans. This is one of the reasons why we have so many kinds of soy bean food like Miso, Tofu, Soy sauce, Yuba, Soy milk, Natto, Abura-age, Koya Dofu, Goma dofu (sesame), Kurumi dofu (Walnut) etc. Also, those foods are good for long storage and we need variation for not being tired to eat. Actually "Salad" -- eating fresh vegetables -- is not so old an eating custom for this country. One of feature of Shojin Ryori and Japanese traditional food would be time-consuming preparation like boiling, removing harshness, etc. This and this are nice articles about Shojin Ryori. Check them out.
By the way, some temples serve Shojin Ryori for people like a restaurant. And there are also Shojin Ryori restaurants. However I must tell you they are expensive! Like I wrote, I understood they are sophisticated, elaborate, but... still expensive. I ate Shojin Ryori a long, long time ago in Kyoto when I was a kid. I remember I was amazed to know it was just Yuba because I thought it would be hum. Shitake mushroom tasted like abalone, Koya Dofu tasted like chicken, etc. I really wanted to find a nice recipe site in English, but there is no good one. I wish this temple blog made an English page.