According to one version the Bullfrog was always ridiculing the
great gambler Ûñtsai'yi, "Brass," (see the story) until the latter
at last got angry and dared the Bullfrog to play the gatayû'sti
(wheel-and-stick) game with him, whichever lost to be scratched on
his forehead. Brass won, as he always did, and the yellow stripes on
the Bullfrog's head show where the gambler's fingers scratched him.
Another story is that the Bullfrog had a conjurer to paint his head
with yellow stripes (brass) to make him appear more handsome to a
pretty woman he was courting.