Shobo

A shobo is a weapon, similar to the Emei piercer of China, which was used by the ninja of Japan for striking pressure points on an opponent. It was a piece of wood that was gripped by the wielder and was hung by a ring worn on the middle finger. Some versions were rings with a wooden peg attached on top. The ends were exposed and were usually shar...
Found on http://en.wikipedia.org/wiki/Shobo

shobo

'the true law', the first period of Buddhism
Found on http://www.encyclo.co.uk/local/20455

shobo

A shobo was a small weapon that was used for striking pressure points within the body, the neck was the best place to strike. It was a ring fitted on the middle finger and a piece of sharp/dull wood attached, there are many variants of this weapon.
Found on http://www.swordsknivesanddaggers.com/ninja-weapons-glossary.html
No exact match found