Jutte

A jitte (十手^?, literally "ten hands") is a specialized weapon that was used by police in Edo period Japan. It is also spelled jutte.

In feudal Japan, it was a crime punishable by death to bring a sword into the shogun's palace. This law applied to almost everyone, including the palace guards. Due to this prohibition, several kinds of non-bladed weapons were carried by palace guards. The jitte proved particularly effective and evolved to become the symbol of a palace guard's exalted position.

In Edo period Japan the jitte was a substitute for a badge, and it represented someone on official business. It was carried by all levels of police officers, including high-ranking samurai police officials and low-rank samurai law enforcement officers (called okappiki or doshin). Other high-ranking samurai officials carried a jitte as a badge of office, including hotel, rice and grain inspectors (aratame). The jitte is the subject of the Japanese martial art of jittejutsu.

Jitte may have a small pointed tip or blade attached to the tsuka and hidden in the boshin. Jitte could be highly decorated with all manner of inlays and designs or very plain and basic depending on the status of the owner and the jitte's intended use. Jitte could range in length from around 12 inches to over 24 inches. The modern jitte is about 45 cm (18 inches) long with no cutting edge and a one-pronged tine, called kagi, about 5 cm long starting just above the hilt and pointing toward the tip sentan. A popular misconception is that the kagi is used to catch a sword. It could possibly be used for this purpose, but the hook's proximity to the hand would make it rather dangerous. When faced with a swordsman, a more likely use for the hook would be to capture and arrest the blade after blocking it with the boshin. The kagi's more common use is to hook into clothing or parts of the body like the nose or mouth, or to push into joints or other weak points on the body. It also could be used to hook the thumb while holding the weapon backwards, to allow different techniques such as punches and blocks, very 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.

...
Wikipedia