Shandong Mahjong covers Jinan, Yantai, Weihai, and Rizhao, and each of those cities has its own twist. This guide covers the shared rules, plus where the regions split.
穷胡 gets mistranslated as 'Poor Win' a lot, but in Dalian's dialect it means restricted winning conditions. You need to know what counts before you start playing.
Wuhan Mahjong is nicknamed 'Open Mouth Mahjong' because open melds are the whole point. Add wildcards, get rid of your Red Dragons, and watch the score multipliers stack.
Tianjin Mahjong only lets you call triplets and win by self-draw. Add a wildcard tile and a pre-round challenge ante, and you've got a variant that rewards patience over speed.