According to an inventory of military equipment compiled during the Bunkyu years (1861–1864), the shell was originally given by Takeda Shingen to Sanada Yukitaka along with a battle bell. Although the exact time is not confirmed, there is an incription on the bell indicating it was made in 1557 which gives us an idea that it could be during the battle of Kawanakajima that spanned between 1553 and 1561 in which both Takeda Shingen and Sanada Yukitaka were involved. From Yukitaka it passed to his son Sanada Masayuki and then to Masayuki’s son Nobuyuki, the first lord of the Matsushiro domain. The object is therefore presented as a Sanada heirloom linked to the Kawanakajima campaigns and the later warrior culture of the Matsushiro castle town. In the Sengoku period such conch trumpets, fitted with carrying cords and nets, were blown to indicate the start of a battle and stir the spirits of the troops.