How to Defend in Riichi Mahjong: A Beginner's Guide
Winning hands matter, but one big deal-in can erase a whole night's gains. Defense is the skill of reading when opponents are dangerous and finding safe tiles to discard until the storm passes.
When should I switch from offense to defense?
Switch to defense when (1) an opponent declares riichi, locking in tenpai with a hidden wait; (2) someone calls into an obvious big shape such as all-honors or a single-suit flush; (3) the round is late and your own hand is far from tenpai. The further you are from winning and the closer they are, the more attractive defense becomes.
What is genbutsu (safe tile)?
Genbutsu (็พ็ฉ, literally "the actual thing") is any tile that the threatening player has already discarded โ by furiten rule, they cannot ron on it. Against a riichi player, every tile already in their discard pile is genbutsu and stays safe for the rest of the hand, making it the gold-standard safe tile to lean on.
What is suji?
Suji (็ญ, literally "line") is the inference that tiles three away from a discarded number are likely safe against a two-sided wait. If your opponent discarded 5m, then 2m and 8m are suji-safe โ a 3m-4m or 6m-7m ryanmen would have included 5m as a wait, which the opponent wouldn't then discard. Suji is a probabilistic guide, not a guarantee: shanpon, tanki and kanchan waits can still hit.
What is no-chance, one-chance and kabe?
These are wall-reading defenses based on how many copies of a tile are already visible (in discards or your own hand). If all four copies of a tile are visible, that tile is "no chance" to be the connector of a kanchan wait or the head of a pair wait โ three visible is "one chance". Kabe (ๅฃ, "wall") uses the same logic to rule out specific waits: if all four 5p are visible, no opponent can be waiting on a 4p-7p ryanmen that needs 5p in the middle.
When should I just fold completely (betaori)?
Fold completely (betaori, ๅฎๅ จ้ใ) when your hand is too far from tenpai to recover before the danger clears. Rule of thumb: 2-shanten or worse with a riichi out, fold by default. Betaori means picking the safest tile every turn even at the cost of breaking your own shape โ losing a few hundred to ryuukyoku is much cheaper than dealing into a mangan.