Jitte

A jitte (十手, "ten hands") is a blunt melee weapon that was used by police in Edo-period Japan (1603–1868).

[2][3] Other high-ranking samurai officials carried a jitte as a badge of office,[4] including hotel, rice and grain inspectors (aratame).

[7] Jitte may have a small point or blade attached to the hilt (tsuka) and hidden in the main shaft (boshin).

It also could be used to hook the thumb while holding the weapon backwards, to allow different techniques such as punches and blocks, similarly to a sai.

The jitte can also be used in much the same manner as other short sticks or batons, to strike large muscle groups and aid in joint manipulation.