Tips
World Jan is short: three sets, nine tiles, four hands. The CPU was tuned with thousands of matches played against itself before the game had a screen, and the numbers from those matches say a lot about how to beat it. This page is what they say.
The race is to tenpai
Riichi is automatic and there is no furiten: as soon as you are one tile away your hand locks, and any winning tile, drawn or discarded, wins. Folding is nearly impossible, because the game discards for you. A hand is therefore a race to be one tile away first, with the widest wait you can manage.
In self-play a hand lasts about 22 to 25 turns per player at Normal and Hard, and exhaustive draws are rare: under 1% of hands. Someone almost always wins, so the question is only who gets there first.
Routes before Triplets
There are 3 copies of each tile. A Triplet needs all three copies of one tile in your hand, and the CPU may hold or discard one; a Route needs one copy each of three different tiles, with nine copies in play. Routes are far easier, and they pay a point each plus Grand Tour when all three sets are Routes.
Keep a pair only when you can Pon it: the CPU's discard completes the Triplet at once. Otherwise break pairs towards Routes.
Spend the Globe on the hard set
4 Globes are in the wall and a Globe can replace one tile in each set. About a quarter of winning hands use one. Use it where a real tile is least likely to come: the third copy of a Triplet, or a Route tile the CPU has already discarded.
Pure, a hand with no Globe, pays three points, but do not keep a hand waiting for it. A Globe that wins now is worth more than three points later. Hold out only when the missing tile is one you would draw anyway.
Call when it brings tenpai
Pon and Chi save turns but give up Concealed, one point. The Normal CPU calls only while it is still two or more tiles away and takes the last step concealed; Hard calls for the last step too and never folds, and that is what made it stronger in testing: calling more, folding never. Copy it when you are behind in the match, stay concealed when a single cheap hand will not change the result.
A call also tells the CPU about your hand. Hard avoids discarding tiles you could call before you are in riichi, so once you start calling, the tiles you want come less often.
Make the geography stack
Most yaku are groups of countries, and they overlap. Three Routes from Peru, Chile and Mexico are Grand Tour, Pacific Rim, Ancient World and New World: 3 + 3 + 1 + 3 + 1 plus the win. Three Routes from Japan, New Zealand and Canada are Grand Tour, Natural Wonders, Pacific Rim and New World. Three Routes from one region are One Region plus Grand Tour plus Old or New World.
Look at the colours of your starting hand. If six or seven tiles share a region or a group, the hand is already half way to a stack; if they are scattered, play for speed and take the win point.
Know the three levels
Easy picks at random among its three best discards, so it wanders: about 32 turns a hand against itself. Normal plays the best discard and calls only while it is still two or more tiles away. Hard calls to reach tenpai sooner, never folds, weighs the danger of each discard against your riichi, and avoids feeding your calls. In self-play Hard beats Normal about 55% of the time and Easy about 90%.
Against Hard, do not expect it to feed your riichi and do not wait for it to fold. Against Easy, a slow valuable hand is affordable.
Play the match, not the hand
A match is 4 hands and the higher total wins. A yakuman is worth 3,000 and settles most matches by itself, but they are rare; a typical winning hand is worth about 900. In the last hand, if you are behind by more than one ordinary hand, build value: Grand Tour and a group yaku. If you are ahead, win fast and cheap, or stay tenpai for the no-ten payment if it ends in a draw.
As dealer, winning repeats the hand (renchan) and the next win pays an extra point; as the other player, a quick win breaks the repeat.
The numbers come from the game's self-play simulation (hundreds to two thousand matches per CPU pairing), recorded in the project's notes in October 2026 after the Globe count and the Hard CPU were tuned.