A saihai was a baton

Baton (symbol)

The ceremonial baton is a short, thick stick, carried by select high-ranking military officers as a uniform article. The baton is distinguished from the swagger stick in being thicker and less functional . Unlike a staff of office, a baton is not rested on the ground...

 carried by samurai

Samurai

is the term for the military nobility of pre-industrial Japan. According to translator William Scott Wilson: "In Chinese, the character 侍 was originally a verb meaning to wait upon or accompany a person in the upper ranks of society, and this is also true of the original term in Japanese, saburau...

 commanders. The saihai or sai-hai was a sign of rank and a signal device.

Appearance and use

A saihai usually consisted of a lacquer

Lacquer

In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required...

ed wood stick with metal ends. The butt had a hole for a cord for the saihai to be hung from the armor of the samurai when not being used. The head of the saihai had a hole with a cord attached to a tassel of strips of lacquered paper, leather, cloth or yak

Yak

The yak, Bos grunniens or Bos mutus, is a long-haired bovine found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. In addition to a large domestic population, there is a small, vulnerable wild yak population...

hair. The saihai first came into use some were during the 1570s and the 1590s between the Genki and Tensho year periods. Large troop movements and improved and varied tactics required commanders in the rear to be able to signal their troops during a battle.