16 BIT
MAHJONG

Here is the rule that catches almost everyone.

PUNG AND KONG — FROM ANYONE

If any player at the table discards a tile you hold two of, you can pung it. Three of, you can kong it. It does not matter who discarded.

CHOW — FROM ONE PLAYER ONLY

You can only chow from the player who plays immediately before you.

That is the player on your LEFT — the one whose discard you see right before your own turn starts.

If anyone else discards the exact tile that completes your run, you cannot take it. You watch it go.

WHY THIS RULE EXISTS

Think about what a chow does to the turn order. A pung or kong is rare enough that jumping the queue for one is fine. But runs are common — if you could chow from anyone, the turn order would barely survive first contact.

Restricting chow to the player right before you means the tile was about to reach you anyway. You are taking your own turn slightly early, not stealing someone else's.

WHAT THIS MEANS IN PLAY

The player to your left is your supply line. Watch what they discard more closely than anyone else's — for runs, they are your only source besides the wall.

And in the other direction: the player to your RIGHT can chow from you. If they are visibly collecting dots, think twice before feeding them a dot.

One more restriction: chow only works on suit tiles — bamboo, characters, dots. Winds and dragons have no sequence, so there is nothing to run.