Iron Tanaka Toryusai School tsuba signed "Takahashi Toshitsugu". At first Toshitsugu was a student of Akao Yoshitsugu, however later in his life he became a student of Tanaka Kiyotoshi. 

Here is a beautiful example of his work in Tanaka School style. 

Published in "Japanese Sword Fittings & Metalwork in the Lundgren Collection"

This tsuba was purchased for a client and therefore is not offered for sale.