Riichi Mahjong is a variation of mahjong that greatly incentivizes keeping your hand closed and entering “riichi.” It is quite different from Chinese mahjong, I think.
Here are some general tips to start winning immediately.
– Never use kongs, pongs, chows. Only use ron (calling the win). It is rarely worth it to open your hand except to prevent another player from winning. Riichi adds a ton to your score on average and makes it much easier to form a hand.
– Again, just go for riichi.
– Discard the winds and dragons in the beginning. Generally, the order is other winds > dragon > your wind, but it doesn’t matter; they rarely improve your score by much even when you luck out. The only time you unambiguously should keep them is when you have a three of a kind. Even when you have two of a kind of a dragon, the odds of drawing the third yourself are not in your favor. If you have two of a dragon/wind and see the third player, don’t be afraid to discard the pair, it often helps form the rest of the hand.
– Focus on the numbers tiles. Specifically, focus on straight melds. Three and four of a kind look “good” from a poker perspective, but going for them can make things more difficult. A [2 2] is more difficult to get a meld with than a [2 3] since you only have two tiles that can complete the former and eight tiles the latter. Four kinds aren’t worth more and can decrease your score since they require declaring “kong” and opening your hand.
– Discard 1s and 9s that are more than one tile from a meld. i.e., [7 9] is ok because an eight will complete it, but  with no 8 or 7 is bad. – If you have a choice between discarding 1/9 or something else, discard the 1/9 because you can get a small bonus by not owning 1s or 9s.
– Try to leave multiple openings when forming melds. For instance [2 2 3] can become melds [2 2 2] [1 2 3] [2 3 4], so it is marginally better to keep the extra  instead of discarding it for [2 3].
– PRESS (X) FOR HIDDEN OPTIONS – When your hand is getting close to complete, start spamming (X) on your turn to check for riichi. When getting riichi, use the left arrow and right arrow to switch between the tiles to discard. Check the upper right-hand corner because it lists the tiles you need to win if you discard the selected. Having two distinct tiles that you’re waiting for is generally better since it can be impossible to win if the opponent has three of a kind of the exact tile you need.
– Riichi: declaring riichi locks your hand and bets 1000 points. If the game ends in a draw, you will win back your 1000 points, and I think 1000 from each player. However, if someone else wins, you will lose your 1000 point bet to enter riichi. There is a strategy surrounding whether to declare riichi or not, but don’t worry about it to begin with. It’s generally to your advantage to always riichi where possible.
– If you’re interested in the dora you can look it up, but I wouldn’t worry about it to start with. Value the Dora tile slightly more highly, but don’t force it.
– To come out with a profit, not getting hit with someone else’s ron is as important as winning the round. Don’t worry about this, to begin with (it’s difficult to predict what tile they need), and focus on your hand.
– Turn on the “red Dora” and turn off the requirement for two han, since this makes it easier to win and score points. Turn on two han if your only goal is scoring a giant hand since this makes it more difficult for the AI to cheese.
– It’s hard to notice, but the beginner table is slightly easier. They tend to win with smaller hands.
– When you get blue-balled and pissed off, remember, This is what mahjong is about. This is the quintessence of Yakuza 0.