The splitting force of Vipukirves™ is considerably stronger than with a traditional axe. Strike and loosen! Vipukirves™ has an ingenious design. Upon striking the log, it automatically turns to the right and detaches the chopped portion from the log. Vipukirves™ functions like a conventional axe with the exception that the user must loosen his/her the grip on the handle when the blade strikes the log. Chopped sections are removed with a single strike and the blade doesn't become lodged in the log, but keeps it in the same place and ready for the next strike."
From Evan Kahn