Riichi strategy: Difference between revisions

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== Considerations for riichi ==
== Considerations for riichi ==
Once again, riichi is a discretionary play.  In fact, in all instances of considering and calling riichi, risk is involved.  Therefore, various factors must be considered before employing using riichi.  At the same time, many plays involving riichi are highly recommended.  Employing riichi is a matter of the current game state.
Once again, riichi is a discretionary play.  In fact, in all instances of considering and calling riichi, risk is involved.  Therefore, various factors must be considered before employing using riichi.  At the same time, many plays involving riichi are highly recommended.  Employing riichi is a matter of the current game state.
=== Scoring ===
Generally, declaring riichi will increase the score of a hand substantially. In addition to providing one guaranteed extra han towards the hand, it grants the opportunity to grab additional increases in ippatsu and uradora. For hands that are not close to mangan limit, declaring riichi will triple the hand's score on average. In general circumstances, this huge increase in reward alone is enough to offset any concerns riichi may raise, which is why it is such a popular move. However, hands which are already high in score will receive significantly less benefit from riichi, and the scoring situation may mean that the extra score is pointless.
=== Intimidation ===
By declaring riichi, the player exerts pressure on the other players, as hands that are not yet in tenpai will be in a significant disadvantage when trying to contest another hand that is already in tenpai. As such, declaring riichi can easily intimidate other players into defending instead of attempting to win the hand, and even if they attempt to contest it, they may end up becoming more cautious and becoming less offensive in general. Of course, this is not guaranteed to work, especially if the point standings force some other players to take on offense at all costs. However, the advantage of having an early tenpai hand is high enough to offset this in general.
=== Winning chance ===
Obviously, by pressuring other players into defending, one is essentially lowering their chance of winning. Assuming that the hand has other yaku and thus declare Ron without riichi, declaring riichi reduces the hand's chance of winning by about 40%. Generally this is offset by the increase of hand value, but not always. On the other hand, there are some hands which have such ridiculously low chance waits (single tile wait on dora, for example) even without riichi, that declaring riichi actually doesn't really reduce the winning rate at all, and pressuring other players into defending means that one is also reducing the chance of other players winning the hand afterwards.
=== Hand lock ===
By declaring riichi, one is locking their hand for the rest of the round. This means that they cannot change the hand to get a better wait, nor can they choose to defend if another player decides to contest the Riichi. This is really the most major risk of declaring riichi. Generally, the hand that is first to tenpai has significant advantage over other hands and thus the reward is well worth the risk, but especially if the hand's shape is not good, or if the risk of dealing in is greater than the reward of winning the hand with additional value, then it can be a bigger point of consideration.


=== Damaten ===
=== Damaten ===
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When the game is closer to its end (generally around the second half, but the point may become earlier if particularly large wins and losses have been going on), point standing becomes more and more of a concern as opportunities to overturn difference become scarcer. Players who are ahead may thus become more cautious, with riichi's risks amplified for them, amongst other considerations.
When the game is closer to its end (generally around the second half, but the point may become earlier if particularly large wins and losses have been going on), point standing becomes more and more of a concern as opportunities to overturn difference become scarcer. Players who are ahead may thus become more cautious, with riichi's risks amplified for them, amongst other considerations.
=== Hand lock ===
By declaring riichi, one is locking their hand for the rest of the round. This means that they cannot change the hand to get a better wait, nor can they choose to defend if another player decides to contest the Riichi. This is really the most major risk of declaring riichi. Generally, the hand that is first to tenpai has significant advantage over other hands and thus the reward is well worth the risk, but especially if the hand's shape is not good, or if the risk of dealing in is greater than the reward of winning the hand with additional value, then it can be a bigger point of consideration.
=== Hand shape and waits ===
After a riichi call, the likelihood of the hand winning places itself on its hand shape and [[machi|tile waits]]. Hands with waits of three tiles or greater, such as [[ryanmenten]] or [[sanmentan]], have a favorable chance of winning, while one tile waits like [[kanchan]] or [[tanki]] are less likely to win. Since pretty much all the risks associated with riichi is only if the hand fails to win, having a hand with good shape waits to win obviously means that they're less of a concern. Bad shape waits may be more pressured to keep the possibility of failure in mind, as well as the possibility of changing the hand into having a better wait.
=== Intimidation ===
By declaring riichi, the player exerts pressure on the other players, as hands that are not yet in tenpai will be in a significant disadvantage when trying to contest another hand that is already in tenpai. As such, declaring riichi can easily intimidate other players into defending instead of attempting to win the hand, and even if they attempt to contest it, they may end up becoming more cautious and becoming less offensive in general. Of course, this is not guaranteed to work, especially if the point standings force some other players to take on offense at all costs. However, the advantage of having an early tenpai hand is high enough to offset this in general.


=== Point standing ===
=== Point standing ===
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When the game is closer to its end, point standing can affect the decision to declare riichi or not in many ways. For starters, players who have a large lead will be more cautious, and the risk of less win rate or hand locking become amplified for them, while the reward of increasing value and intimidation are lessend. Players who are greatly behind, on the other hand, will likely cling to Riichi's increase in value, as all the risks in the world no longer matter to them. Players who are in the middle will also start having specific point goals for their hands to achieve their goals - one player may choose to damaten their hand because it is large enough to overcome the difference to another player's score, while another may choose to declare riichi because they need the extra points to do so. For these players there are no fast and hard rules to adhere to any more - they simply have to analyze their own situation and decide what goals to set for their hands, and whether if declaring riichi would fit (or not fit) into their plan.
When the game is closer to its end, point standing can affect the decision to declare riichi or not in many ways. For starters, players who have a large lead will be more cautious, and the risk of less win rate or hand locking become amplified for them, while the reward of increasing value and intimidation are lessend. Players who are greatly behind, on the other hand, will likely cling to Riichi's increase in value, as all the risks in the world no longer matter to them. Players who are in the middle will also start having specific point goals for their hands to achieve their goals - one player may choose to damaten their hand because it is large enough to overcome the difference to another player's score, while another may choose to declare riichi because they need the extra points to do so. For these players there are no fast and hard rules to adhere to any more - they simply have to analyze their own situation and decide what goals to set for their hands, and whether if declaring riichi would fit (or not fit) into their plan.


=== Hand shape and waits ===
=== Scoring ===
 
Generally, declaring riichi will increase the score of a hand substantially. In addition to providing one guaranteed extra han towards the hand, it grants the opportunity to grab additional increases in ippatsu and uradora. For hands that are not close to mangan limit, declaring riichi will triple the hand's score on average. In general circumstances, this huge increase in reward alone is enough to offset any concerns riichi may raise, which is why it is such a popular move. However, hands which are already high in score will receive significantly less benefit from riichi, and the scoring situation may mean that the extra score is pointless.
 
=== Winning chance ===


After a riichi call, the likelihood of the hand winning places itself on its hand shape and [[machi|tile waits]]. Hands with waits of three tiles or greater, such as [[ryanmenten]] or [[sanmentan]], have a favorable chance of winning, while one tile waits like [[kanchan]] or [[tanki]] are less likely to win. Since pretty much all the risks associated with riichi is only if the hand fails to win, having a hand with good shape waits to win obviously means that they're less of a concern. Bad shape waits may be more pressured to keep the possibility of failure in mind, as well as the possibility of changing the hand into having a better wait.
Obviously, by pressuring other players into defending, one is essentially lowering their chance of winning. Assuming that the hand has other yaku and thus declare Ron without riichi, declaring riichi reduces the hand's chance of winning by about 40%. Generally this is offset by the increase of hand value, but not always. On the other hand, there are some hands which have such ridiculously low chance waits (single tile wait on dora, for example) even without riichi, that declaring riichi actually doesn't really reduce the winning rate at all, and pressuring other players into defending means that one is also reducing the chance of other players winning the hand afterwards.


== Oikake riichi ==
== Oikake riichi ==
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