|Japanese Plow (notice grip), 1914-18 photo by A.Davey|
You may have seen the practice of linking fingers in shinto (こりてくみ koritekumi, みてわざ mitewaza), or in mikkyo (手印 shuin). Two common variations are 本手 honte for yielding or being gentle, and 逆手 gyakute for vigorous strength. 観音菩薩 Kannonbosatsu often assumes the honte finger position for mercy, while 勢至菩薩 Seishibosatsu applies the gyakute method for wisdom.
So we may apply this to 手の内 tenouchi and holding a weapon:
- If you are gripping honte style, hold the weapon across your palm with the middle finger and thumb coming together. This method is preferred for freedom and flexibility.
With gyakute, you may shift the weapon in your palm so the index finger and thumb come together. Gripping in this fashion shows strength and power.
That's it. Most other variations are specialties for very specific situations or for specialized weapons. You may try to get tricky, but human hands have been holding tools and weapons since our ancestors first grew thumbs.
Of course what I'm not sharing is the knowledge of how or when to use these grips. You must speak to your teacher for that. Only real training can fill in the blanks.