Riichi Mahjong Defense Guide
1. Basics
Betaori is a defense style that gives up on agari and focuses only on avoiding a deal-in.Prioritize safe discards over building your hand.With one safe tile for every turn left, you can hold out to the end.
1.1 Safety
Without a safe tile, pick the tile the fewest waits can hit.Risk generally rises down the list. Honor safety varies widely with how many copies are visible.
1
2
3
KabeKabe→
All four copies of a tile are visible, so every ryanmen wait using that tile is gone. Relatively safe. Count your hand, the discards, and the dora indicator together.4
4.1
4.2
2. Reading
2.1 Genbutsu
2.2 Suji
A tile three ranks away from a genbutsu tile is suji. 1-4-7, 2-5-8, and 3-6-9 form the suji lines.Suji only stops ryanmen. Tanki and shanpon can still hit any suji tile. Kanchan and penchan cannot be ruled out either.A 4, 5, or 6 is naka-suji only when the suji on both sides are genbutsu. One side alone makes it kata-suji.Kata-suji is far riskier than naka-suji.
2.3 Kabe
When all four copies of a tile are visible, that tile forms a kabe. Count your hand, the discards, and the dora indicator together.If 3 forms a kabe, 1 and 2 cannot deal into a ryanmen. 2 is safe from kanchan as well.If 4 forms a kabe, 1 is still open to a 2-3 ryanmen, so it is not safe. In short, kabe is strongest on 2, 3, 7, and 8.Kabe cannot stop tanki or shanpon.
2.4 Honors
3. Discarding
3.1 Order
Discard the safest tile first, even if it breaks a set or your tenpai.Do not discard a suji tile while you still hold a safe tile. One turn later, you may have more safe tiles.With several safe tiles, keep the ones that are also genbutsu against other players. That prepares you for a chase riichi.As genbutsu piles up, tiles not yet shown safe grow riskier, because the remaining waits narrow just as much.
3.2 Chase riichi
Against two riichi players, only a tile that deals into neither is a safe tile.After the second riichi, a tile both players pass up for ron is genbutsu against both.If the first riichi player lets the second player’s declaration tile pass without a ron, that tile is genbutsu against both as well.Kabe and honor counts apply to both players equally. Suji is read separately for each player.A tile that is suji against both can beat one that is genbutsu against only one.
3.3 Dangerous tiles
With no genbutsu, honor, kabe, or suji tile left, pick from the dangerous tiles. Even then, some are less dangerous than others.1 and 9 are the least dangerous; 4, 5, and 6 are the most. The closer a tile sits to the edge, the fewer waits can use it.Without an edge tile, discard the tile whose copies and neighbors are most visible. The more you see, the fewer waits remain on it.More visible copies of the tile itself mean fewer tanki and shanpon waits.More visible neighbors mean fewer ryanmen and kanchan waits using it.