Everyone creates a spirit inspired by an animal or a natural element. Write a name, a parodistic description, a domain: you bring fortune or misfortune to this domain, choose it or find out playing, don't say it to the other players. Choose a first player. Every scene starts in the same small medieval Japanese village. First player describes how his spirit enters the village and how he shows itself to the inhabitants or what he is doing something when they find him. Every other player clockwise: first tells how children react, second how women react, third how men react. Inhabitants players can describe elements of the village. Spirit describe how he reacts to human reaction. Go reaction by reaction, until the scene ends. The Spirit, or the first player not playing inhabitants, can end the scene. Cut the scene when you have a custom. Who ended the scene write a statement on the "Tradition Paper": spirit name, one thing done by the one of the three inhabitants categories, the spirit write how change on his domains, "When Kazuiaku arrived, children hid themselves under the woman skirt. Rice production was generous". Game ends when every spirit have played a scene.
I hope this will make give you the feeling of creating your own village and your own customs. Like creating your little version of a Shintoism Kamis. Hopefully reading the Custom Paper will leave you with your personal tradition you will remember and read in the future. A longer version of the game will be found in future at my website https://designdrill.wordpress.com/ Thanks to mammut rpg for always keeping me in the rpg loop even when life keeps me away from roleplaying.