The Kumasaka Family in the United States

"The family's crest is called chigai-bushi-mon, or combined diamond (the shape, not the jewel) crest. It is a variant of the hishi-mon, or diamond crest. The diamond, or rhombus, shape is called hishi-gata in Japanese because it resembles the nut of the water chestnut (hishi). Hishi crests are especially well-known as the crest of the Takeda family. 

The Takeda were a military family who began their rise in the Kamakura period (1192-1333) and had great power in the Warring States Period (1470-1570).  The Takeda first adapted the hishi-mon for use of their armor and only later began to use it more generally as a family crest.  Branch families of the Takeda also used the hishi-mon, but of a different design from that of the main family. According to an historical record dated 1393, the Lord of Izu Province (a post which carried no real power at that time) Takeda Nobuari wore the same crest as the Kumasaka's, embroidered on his formal attire when he had an audience with officials of the shogunate.

There are varied kinds of hishi-mon. In the Edo period (1603-1867) the crest was adopted by many families, such as daimyo families in Nanbu, Yanagisawa, Goto, Yamaguchi and Matsumae domains, as well as more than 450 direct retainers of the shogun.  Hishi-mon are among the most widely-used crests in Japan."

The mon can be seen in Akira Kurosawa's movie, "Ran."