1 Mon 'Kan'eitsūhō' reverse 文 BUN

The Kan'ei Tsūhō series was authorized in 1636 under the Tokugawa shogunate as part of a broader effort to standardize currency across a fragmented monetary system still relying on a patchwork of older Chinese-style cash coins and regional issues. By the 1660s, numerous private and domain mints had received casting licenses, producing coins of wildly inconsistent quality — the reverse 文 (bun) mark was introduced specifically to distinguish output from the Sakamoto mint in Ōmi Province. The three DHJ references reflect documented die variations among survivors, not separate issues.