Boshi ken

Boshi is the tip of a sword, the first few inches and ususally in samurai sword style moved the most common part used for cutting as it moves the most during a cut. Boshi Ken is the handshape or strike where your thumb is placed in a position so it looks like the tip of a sword, hence boshi-ken.

The first rule of Ninjutsu is dont get hit!!! The second rule is dont forget the first rule.