The game pieces are small and round and each side would have a different color - that's about all I can tell from the pictorial evidence, both in Kamakura-period emaki and Edo woodcuts. White and black seem common. There's an Edo period dice shaker in "Asian Games" made out of a small section of bamboo and lacquered in black and gold. I've found of people playing sugoroku.

So yeah, I'm extrapolating like mad.