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Riichi strategy: Difference between revisions
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add the standard riichi criteria (found in many mahjong strategy books)
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(add the standard riichi criteria (found in many mahjong strategy books)) |
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Calling [[riichi]] comes with various considerations. While riichi does give a high score bonus, it also alerts players that you are in tenpai, and prevents you from [[defense|defending]]. Therefore, some discretion should be used before declaring riichi. | Calling [[riichi]] comes with various considerations. While riichi does give a high score bonus, it also alerts players that you are in tenpai, and prevents you from [[defense|defending]]. Therefore, some discretion should be used before declaring riichi. | ||
== Assessing riichi | == Assessing riichi == | ||
[[Image:Indefensible riichi.png|thumb|right|250px|Riichi does not let you respond to [http://tenhou.net/0/?log=2012111209gm-0009-7447-x33034e7e5279&tw=2&ts=4 any conditions that change in the future].]] <!--Aligns with the disadvantages section better here--> | [[Image:Indefensible riichi.png|thumb|right|250px|Riichi does not let you respond to [http://tenhou.net/0/?log=2012111209gm-0009-7447-x33034e7e5279&tw=2&ts=4 any conditions that change in the future].]] <!--Aligns with the disadvantages section better here--> | ||
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** A riichi call prevents you from [[targeting]] a specific player to ron off of. | ** A riichi call prevents you from [[targeting]] a specific player to ron off of. | ||
* A "riichi stick" of 1,000 points is spent to call the riichi, with the hopes of winning it back. However, other players may win the hand and capture those 1,000 points instead. | * A "riichi stick" of 1,000 points is spent to call the riichi, with the hopes of winning it back. However, other players may win the hand and capture those 1,000 points instead. | ||
== Alternatives == | |||
There are two main alternatives to riichi: | |||
* [[Damaten]] - entering tenpai without riichi. | |||
** Even if the hand has no yaku, any closed hand can gain yaku with [[menzen tsumo]]. | |||
* Going back to [[iishanten]] - this may be done - rarely - in order to look for wait upgrades (a hand in iishanten tends to have more upgrades than tenpai). | |||
== Speed == | == Speed == | ||
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Due to these advantages, a "head start" riichi is very powerful. Even if an opponent attacks into your riichi, you have chances to win before then. Declaring riichi ''just'' for intimidation is not effective, but any sort of value can make the riichi powerful. | Due to these advantages, a "head start" riichi is very powerful. Even if an opponent attacks into your riichi, you have chances to win before then. Declaring riichi ''just'' for intimidation is not effective, but any sort of value can make the riichi powerful. | ||
Conversely, a chasing riichi (riichi after another player has declared riichi) is weaker for the same reasons. You should not shy away from chasing riichi, though; if you want to attack against an opponent, you want all the value you can get. | Conversely, a chasing riichi (riichi after another player has declared riichi) is weaker for the same reasons. You should not shy away from a chasing riichi, though; if you reach tenpai safely, and want to attack against an opponent, you want all the value you can get. | ||
== Hand shape and waits == | == Hand shape and waits == | ||
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However, there are a few cases where score does not matter: | However, there are a few cases where score does not matter: | ||
* Past [[mangan]], each han has reduced effectiveness. A [[haneman]]-or-higher hand shouldn't riichi because it is already very valuable, so the score bonus from riichi isn't as impactful. (Going from 6 han -> 7 han doesn't increase score. 7 han -> 8 han is only a +25% boost to score.) | * Past [[mangan]], each han has reduced effectiveness. A [[haneman]]-or-higher hand shouldn't riichi because it is already very valuable, so the score bonus from riichi isn't as impactful. (For example: Going from 6 han -> 7 han doesn't increase score. 7 han -> 8 han is only a +25% boost to score.) | ||
* When first with a large lead, or first during [[all last]]. In this case, damaten helps increase your win rate, allowing you to end the game faster. | * When first with a large lead, or first during [[all last]]. In this case, damaten helps increase your win rate, allowing you to end the game faster. | ||
* When in [[all last]], where both dama and riichi will result in the same final placement (even with a direct hit riichi + 1 ura dora). | * When in [[all last]], where both dama and riichi will result in the same final placement (even with a direct hit riichi + 1 ura dora). | ||
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Players often declare chasing riichi when: | Players often declare chasing riichi when: | ||
* They have no option to defend. | * They have no option to defend. | ||
* They have a strong hand. If | * They have a strong hand. | ||
** If tenpai happens to be reached with a good wait, and chase an opponent's riichi, your win rate far exceeds the deal-in rate. (If the hand is still iishanten when the first riichi is declared, a very strong hand is needed to attack.) | |||
When you do have the option to defend, the decision to push or fold should depend more on [[shanten]], [[tile acceptance]], and wait rather than the value of the hand. | When you do have the option to defend, the decision to push or fold should depend more on [[shanten]], [[tile acceptance]], and wait rather than the value of the hand. | ||
If [[abortive draw]]s are enabled, the hand will end in abortive draw when all four players declare riichi (after the 4th riichi declarer discards a tile). | If [[abortive draw]]s are enabled, the hand will end in abortive draw when all four players declare riichi (after the 4th riichi declarer discards a tile). | ||
== (Average) riichi criteria == | |||
With all these factors in mind, the following is a rough guideline of when to and not to riichi. This list should be taken with a grain of salt - they may change based on the exact hand composition, your opponents hands/discards, point standings, round #, and the current turn #. Of these factors, point standings and round # are the most important. | |||
'''Do riichi:''' | |||
* When first to tenpai, good wait (>= 6 tiles), 1-4 han after riichi. Even a riichi-only hand with a [[ryanmen]] wait is positive value. | |||
* When first to tenpai, bad wait, 2-4 han after riichi. A 2 han 40 fu hand (e.g. riichi tanyao) is also stronger than damaten. | |||
* When declaring chasing riichi, with a hand worth pushing, so long as it's at/below mangan after riichi. | |||
'''Don't riichi:''' | |||
* With haneman+ hands. | |||
* With a mangan (4 han 30 fu) hand with a bad wait. | |||
* With an extreme amount of upgrades. The amount of upgrades need to be very high. In the early game, to delay tenpai there should be: 6 types of tiles (~24 tiles total) for a wait upgrade, or 4 types (~16 tiles total) to double value. | |||
* After point standing analysis. You don't need to riichi with a large lead in all last, or if dama would result in you taking 1st during all last. | |||
==References== | ==References== | ||