A Suna Teppo or Sokutoki
This particular piece was owned by the Sanada clan of Shinano (Nagano), as per the Sanada clan crests. It is about 5cm in size. Ash, including blinding agents such as finely ground salt and peppers was mixed and poured into the chamber. The long, rectangular metal block was the plug, with a belt clip attached.
The unit contained blinding agents to be blown into the face on an enemy
The chain prevented the pieces from being dropped and lost. When facing an attacker, the Suna Teppo could be quickly detached, and carried in the mouth via the mouthpiece, before being blown in the direction of attackers at close range. A thick cloud of blinding “smoke screen” could be blown into the faces of the attacker, allowing for an escape, or a moments grace to cut the opponent down.
Crests of the Sanada clan adorn this Suna Teppo