Is anyone familiar with Buddhist Numerology? Regarding the "numbered" katas (Sanchin, Seisan, Sepai, Sanseiru, Gojushiho, Pechurin, etc.), what is the significance of the numbers and/or relationships to Buddhist numerology?
If you refer to significant numbers in Buddhism there a many. 3 is an important number and so is 108. In some countries 1008 is important. Numbers are used in Buddhism to aid people in remembering teachings such as the Three Jewels and the Noble Eightfold Path. These are incorporated into some martial arts such as wing chun in which its first form, Sil Lim/Lum/whatever Tao, has 108 movements. Well accoring to a book and my teacher but forms vary.
The Taiji form (in Wu style, anyway) has 108 steps. But that is a multiple of three, which is a significant number in Taoism. Bear in mind the influence of Taoism on Chinese Buddhism. Chan (Zen) Buddhism developed in China with a distinctly Chinese and Taoist aspect.
True, 3 is a significant number in many religions, including Christianity. It is also true that the religions of China have a very close relationship.