Betaori
Betaori 「ベタ降り」 ("folding" in English) is a strategy which aims to minimize the chance of dealing into other players' hands. Usually, a player will abandon the prospect of winning themselves. While points can be lost via opponent tsumo or at ryuukyoku, you'd lose less points from these than by dealing in.
Determining safe tiles
When playing betaori, you should discard the safest tiles. For example, if an opponent declares riichi, you should discard safe tiles against that player. This requires deduction from visible tiles, including all discards, dora indicator, and the tiles in the player's own hand. Of course, it also requires the player's active decision to defend (as opposed to continuing to push the hand towards tenpai).
Genbutsu and furiten
Genbutsu 「現物」 is a term for "safe tile" due to furiten. Tiles made safe by the furiten rule are the safest tiles against that particular player.
There are three types of furiten:
- Discard furiten: If a player has discarded any tile they could've won off of, they are in furiten. Thus, any tile that a player discarded is 100% safe against that player.
- Temporary furiten: If a non-riichi hand declines a win, the player is in furiten until their next discard. This means that the tile discarded by the your left player is 100% safe against everyone for that turn only. The tile discarded by the player across from you is 100% safe against your right player, again for that turn only.
- Riichi furiten: If a riichi hand declines a win, the player is in furiten for the rest of a hand. So after a player declares riichi, any tile discarded by anyone is 100% safe against the riichi.
If genbutsu is not available, then defensive strategies like suji and/or kabe should be employed to determine the tile least likely to deal in.
If two tiles are equally safe, try to discard tiles that are less likely to be dangerous against other players. For example, if both 6-pin and 1-pin are safe against a riichi player, discard 6-pin first. That way, if another player declares riichi, the 1-pin is less dangerous.
If two tiles are still equally safe, it is best to discard a tile that does not reduce hand progress. After all, you can prevent opponents from winning by winning yourself.
Mawashiuchi
Mawashi uchi 「回し打ち」 is a strategy distinct to betaori. A "halfway" style, it aims to retain 1-shanten while discarding relatively safe tiles (e.g. suji, sotogawa tiles). A player undergoing mawashi will discard relatively safe tiles, even at the cost of tile acceptance.
When undergoing mawashi, you should constantly evaluate if you should be folding. If a dangerous tile is drawn and can't be used in the hand, mawashi usually is converted to betaori. If it gets too late in the round, it may also be good to fold (it is easier to deal in when late in the round). Conversely, if you hit tenpai in a reasonable timeframe, pushing is generally good.
External links
- Written work on defense in Osamuko