Mark with Japanese Mark: 慶応寅孟夏　於東府墨水辺 "Keiou tora | #458411

慶応寅孟夏　於東府墨水辺 "Keiou tora mouka Tofu Bokusui Atari ni oite". This mark is from a tsuba and was made by Teikan, who worked as a sword engraver (soukenkinkou) in Hitachi Province (present-day Ibaraki Prefecture). Soukenkinkou is the Japanese name for metalworkers who design accessories for bladed weapons. A tsuba is a sword guard designed to protect the hand from contact with the blade. It also balances the weight of the sword.