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Suji: Difference between revisions
move the "4,5,6 not safe unless two suji are cleared" back up to the top. improve advice section & ura suji section
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*[[Shuntsu|Sequences]] are comprised of three sequential tiles. Therefore, an open wait will win off two tiles that are 3-apart. For example, {23} can win off either a 1 or 4 of the same suit. {34} can win off 2 or 5 of the same suit. This continues until you get the intervals of: 1-4, 4-7, 2-5, 2-8, 3-6, and 3-9. | *[[Shuntsu|Sequences]] are comprised of three sequential tiles. Therefore, an open wait will win off two tiles that are 3-apart. For example, {23} can win off either a 1 or 4 of the same suit. {34} can win off 2 or 5 of the same suit. This continues until you get the intervals of: 1-4, 4-7, 2-5, 2-8, 3-6, and 3-9. | ||
*Due to the [[furiten]] rule, if a player has previously discarded any tile they could have won off of, they cannot win from other players. | *Due to the [[furiten]] rule, if a player has previously discarded any tile they could have won off of, they cannot win from other players. | ||
*Therefore, if a tile in a suji interval is | *Therefore, if a tile in a suji interval is discarded, then other tiles in that interval become safer against that player. For example, if an opponent discards a 4, then the 1 of the same suit is safer. This is because, if they had an open wait, it would be subject to furiten. Similarly, the 7 also becomes safer when a 4 is discarded, due to the 4-7 interval. | ||
*However, if a 1 is discarded, 4 does not become safer. This is because there are two different intervals for 4, that being 1-4 and 4-7. In order for 4 to be a "full" suji, both 1 and 7 have to be discarded. The same applies to 5 and 6. | |||
Note: suji also applies to the other forms of furiten. After an opponent declares [[riichi]], then any non-winning tile discarded by anyone becomes safe. Therefore, suji can be applied to these tiles as well. | Note: suji also applies to the other forms of furiten. After an opponent declares [[riichi]], then any non-winning tile discarded by anyone becomes safe. Therefore, suji can be applied to these tiles as well. So if an opponent declares riichi, and the next opponent discards a 4, then 1 and 7 are still considered suji. | ||
==Intervals== | ==Intervals== | ||
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== Defense == | == Defense == | ||
Suji relies on the fact that a player is using a [[ryanmen]] wait, or a related wait like [[ryanmenten]], [[nobetan]], or [[sanmentan]]. Ryanmen itself appears in around ~50% of winning hands, which is common, but not even close to guaranteed. | Suji relies on the fact that a player is using a [[ryanmen]] wait, or a related wait like [[ryanmenten]], [[nobetan]], or [[sanmentan]]. Ryanmen itself appears in around ~50% of winning hands, which is common, but not even close to guaranteed. Hands that do not use ryanmen, like [[toitoi]] and [[chiitoitsu]], are immune to suji. | ||
The middle tiles (4,5,6) have two suji intervals to account for. For example, a 4 has two suji in 1-4 and 4-7. A discarded 1 does not make 4 much safer. In order for 4 to be a "full" suji, both 1 and 7 have to be safe. | |||
Not all suji are equally safe. This is because some tiles can be targeted by [[kanchan]] (24) or [[penchan]] (12) waits. | Not all suji are equally safe. This is because some tiles can be targeted by [[kanchan]] (24) or [[penchan]] (12) waits. | ||
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*Suji 2 and 8, as well as a completed nakasuji (4,5,6), are the next safest. They can be targeted by a tanki, shanpon, or kanchan. | *Suji 2 and 8, as well as a completed nakasuji (4,5,6), are the next safest. They can be targeted by a tanki, shanpon, or kanchan. | ||
*Suji 3 and 7 are the most dangerous, though still reasonably safe. They can be targeted by a tanki, shanpon, kanchan, or penchan. | *Suji 3 and 7 are the most dangerous, though still reasonably safe. They can be targeted by a tanki, shanpon, kanchan, or penchan. | ||
*"Half suji" tiles, e.g. a 4 after only a | *"Half suji" tiles, e.g. a 4 after only a 1 has been discarded, are not much safer than a regular tile. | ||
Suji based off the riichi declaration tile is considered to be more dangerous than normal. This is due to the strength of a ryankan shape. See the [[#Offense|Offense]] section for more information. | Suji based off the riichi declaration tile is considered to be more dangerous than normal. This is due to the strength of a ryankan shape. See the [[#Offense|Offense]] section for more information. | ||
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=== Ura suji === | === Ura suji === | ||
Ura suji is a theory which suggests that: when a middle tile is discarded relatively early, | Ura suji is a theory which suggests that: when a middle tile is discarded relatively early, a nearby tile and its suji become more dangerous. | ||
Say an opponent had a 35 [[kanchan]] in their hand. If a 2 is drawn, then 5 would be discarded from the "235", leaving just a 23 ryanmen shape. The 23 waits on a 1 or 4, so if a 5 is discarded relatively early, then 1-4 becomes more dangerous. Therefore, a discarded 5 makes 1 and 4 into ura suji. If a 4 is discarded later, then the "regular" suji takes priority over ura suji. | |||
According to ura suji: | According to ura suji: | ||
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(Discarded 1/2/8/9 tiles are not particularly noteworthy, since these tiles are often discarded early anyways.) | (Discarded 1/2/8/9 tiles are not particularly noteworthy, since these tiles are often discarded early anyways.) | ||
In the modern day, ura suji is often disregarded. | In the modern day, ura suji is often disregarded. It is true that, if an opponent discards a 5-pin early, then a non-suji 4-pin is at least somewhat more dangerous than normal. However, a non-suji 4-man, 5-man, 4-sou, etc. would also be dangerous tiles. Therefore, knowing about ura suji would not change your behavior. | ||
*If you were folding, you would not discard any non-safe non-suji tiles unless you had to. | *If you were folding, you would not discard any non-safe non-suji tiles unless you had to. Even if you did, you wouldn't discard a middle tile if you could avoid it. | ||
*If you were attacking, you would discard ura suji anyways, because an ura suji is not that much more dangerous than a regular non-suji tile. | *If you were attacking, you would discard ura suji anyways, because an ura suji is not that much more dangerous than a regular non-suji tile. | ||
In addition, ura suji assumes your opponent is going for maximum [[tile efficiency]]. | In addition, ura suji theory assumes your opponent is going for maximum [[tile efficiency]]. | ||
The reason ura suji is not that much more dangerous than normal is because it assumes a (35) kanchan had existed in the first place. The 5-pin could have been an unrelated tile, or it could have been part of a 57 kanchan, or part of a completed 556 shape, or part of a completed 135 shape, etc. Even if the kanchan did exist, an opponent could have drew a 1 or 4 before reaching tenpai. | |||
== External links == | == External links == | ||