4 Mon 'Bunkyūeihō' Bosen, copper alloy, cursive script, CHŪKAKU KETSURIN

The Bunkyūeihō 4-mon was authorized in 1863 as Japan's monetary system strained under the twin pressures of forced treaty trade with Western powers and the massive silver outflows those treaties caused. The chūkaku ketsurin — a recognized reverse wave-pattern deficiency variety — identifies pieces where the inner rim definition collapsed during die production, a known characteristic rather than damage.

Cursive-script 4-mon pieces were produced at multiple furnace operators under domain authorization, which complicates attribution. The 1863–1868 window spans the terminal Tokugawa years through the Meiji Restoration itself.