Riichi mahjong is a four player game that combines the elements of calculation and strategy that is found in chess with the elements of observation, risk assessment, and especially luck that is found in poker.


Calculation involves using information to derive equivalent information. It requires vast amounts of processing ability.

In games like Chess and Go, supercomputers are formidable opponents as the games are mostly about calculation.

The concept of tile efficiency, where choosing the best tile to discard given only information about the player's own hand, falls under calculation. Calculation, though, includes using all of the information gathered. That usually includes, at the least, the opponents' discarded tiles.

Given that players have little control over which tiles they draw and which tiles their opponents discard, calculation may be the most important skill.


Gathering information via the senses about other players and their movements separates live play from online play.

Observation includes:

  • Watching each tile that is drawn and discarded.
  • Watching the opponents' body language.

Observation isn't very useful without good memory.

Reviewing play records is a weaker form of observation.

Having ESP powers heavily augments observations skills.


Strategy would seem to be less important in games involving players with supernatural powers, but that's not necessarily true. Strategy can augment supernatural powers. Adaptive strategies are required for those with and without powers.

Risk assessment

Information gathered has an attached accuracy level, ranging from low to 100% accuracy. Players will try to maximize their chances of winning a match, usually by maximizing the expected value of each hand.


There is a lot useful information that can be gathered. Being able to gather them, remember them, and process them is an important component in mahjong.


Players have little control over which tiles they draw and the tiles in their opponents hands are mostly hidden. Luck is the most important factor in any one particular hand, but may not be the most important factor in games consisting of more hands. Players with supernatural powers are exceptions, though.


Cheating is difficult given that the matches are recorded from multiple angles. The tiles in each players' hand are visible to onlookers, so playing rooms are separated from audiences and commentators. The playing rooms are shielded from electromagnetic waves.

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