Dream with Our Eyes Open

So if a Gojyo-type character were to end up in Edo-era Japan, would he be able to support himself by gambling? This stray thought brought me to this article from the Japan Times Online:

By the middle of the Heian Period (794-1185), gambling had become rampant among the inhabitants of the capital, Heiankyo (present-day Kyoto). People wagered enthusiastically on practically anything: cock fights, horse races, cricket fights and fanciful competitions that made use of flowers, pictures or folding fans.

Around this time professional gamblers, known as bakuto, first appeared. Historical accounts gave details of brawls, killings and robberies involving gamblers, which led to increasingly strict measures to repress their activities. Between 1225 and 1284, the authorities issued no fewer than nine edicts prohibiting gambling.

During the Edo Period (1603-1867), members of the ruling samurai class were discouraged from gambling ... .

What's less clear is what he'd be playing - not cards, which came in with the Portugese, later. From the discussion later in the article, the likeliest thing would be a dice games of various sorts. Hmm ... .