Long-tailed triple tomoe
尾長三つ巴 onaga mitsudomoe

Three comma-shaped tomoe swirling around a centre, here with long tails that wrap the crest. Tomoe are linked to water and whirlpools, so tomoe roof tiles were believed to ward off fire; common on shrine and family crests.
Heian period; widespread on crests and roof tiles from the Kamakura period
The tomoe may derive from the leather arm-guard (tomo) of archers or from a coiled snake, and resembles ancient magatama beads. It appears in the Byōdōin Phoenix Hall paintings (1053) and on eave tiles, where the water-related swirl was believed to ward off fire. Through the archer's tomo it became linked to Hachiman, god of war, and the three-comma form is the Hachiman shrine crest and a common samurai family crest. Long-tailed (onaga) versions are a later stylistic variant.