American-style mahjong against bots, with a coach at your elbow.
Setting up the table…
You
Practice card
Our own practice hands, written in the style of the yearly NMJL card — not the official card (that one is copyrighted and changes every year). Colors show suits: same color = same suit, different colors = different suits. D = the dragon that matches that suit (Red↔Cracks, Green↔Bams, Soap↔Dots); 0 = Soap. X = you may call discards; C = concealed.
Practice rules (what's simplified)
Hands come from the practice card above, not this year's NMJL card. The rules for jokers, calling, joker swaps and payments are the real American rules.
Charleston: the first round (right, across, left) always happens; you choose whether to play the second round (left, across, right). The last pass of each round may be a blind pass. Then there's an optional courtesy pass with the player across: you each pass the smaller number asked for (0–3). Bots never blind-pass.
Bots decide on discards instantly; you get a moment to call whenever you legally can.
A hand whose exposures fit nothing on the card goes dead: you keep playing but can't win. There are no other penalties.
Rewind takes you back to your previous decision (a pass, a discard, or a call) with the same tiles still to come. A game you rewind still counts toward your running totals only once.
Payments: discarder pays double, others single; a self-drawn win is double from everyone; jokerless doubles again (not for Singles & Pairs).