Legend of the Strongest Man Urasawa, which >>12136175
's girl is from, is about the struggles of a manual labourer in modern Japan. That manga was critically acclaimed and was based on Fukumoto's time as a labourer.
Most of the manga I know of are his most famous ones, like Gin + Kin, Akagi, Ten, Kaiji, Zero - all of those involve gambling and/or the underworld in some sense. But his lesser known manga, which comprise something like fourteen titles, are all over the place.
Ten's story was actually pretty common for a mahjong manga when it was first made. Many 1980's manga involved the same kind of setting of a young rookie and the pro who takes him on. Ten is perhaps the most famous because Ten himself was unique to the genre, as was Akagi - both characters had surprisingly more depth than others of the day like Tetsuya.