Kanabō

The kanabō (金棒) was a spiked/knobbed club or truncheon used in feudal Japan as a weapon by samurai and their retainers. Other related weapons of this type are the  nyoibo, konsaibo,  tetsubō (鉄棒), and the ararebo. Related solid iron weapons with no spikes or knobs are the kanemuchi (kanamuchi) and the aribo (gojo/kirikobo).

Description
Kanabō and the other related types of these club like weapons were constructed out of heavy wood, or made entirely from iron, with iron spikes or studs all around the weapon. One or both ends of the wooden type clubs could be sheathed in iron. Kanabō type weapons came in all sizes and shapes with the largest ones being as tall as a man and a two-handed weapon while the smaller lighter ones were primarily one-handed and the length of a forearm. The shape could be that of a baseball bat with a thick heavy end tapering towards a slender handle or they could be straight all the way from the handle to the end, with the shaft being round or multi faceted.

Mythology
The kanabō was also a mythical weapon, often used in tales by oni (japanese demon) since they were reputedly  extremely strong. Today there is a saying in Japanese: "Like giving a kanabō to an oni" — which means to give an extra advantage to someone who already has the advantage (the strong made stronger). A western rendering might be, 'like adding fuel to a fire'.

Use
It has been said that one purpose of the kanabō type of weapons was to smash enemies' armor, bones and the legs of their warhorses. The art of using this cumbersome weapon, kanabō-jutsu or tetsubo-jutsu, consisted of a mastery of both balance and strength; it required great skill to recover from a miss with the heavy club, which could leave a wielder open to a counter-attack.