Mahjong Defense Steps Using Genbutsu and Suji

When new to mahjong, choosing what to discard after an opponent calls riichi (a closed hand tenpai declaration waiting on 1 tile to win) can be puzzling. To stay safe, mastering the basics of mahjong genbutsu and suji is the quickest route. In this article, we follow a hand turn by turn to see which tiles to discard and in what order after a riichi.

Turn 1: Find and Discard Genbutsu from the Discard Pond

Suppose in this diagram, the opponent who called riichi has 5 Man in their discard pond. A tile identical to one already discarded by that opponent is called "genbutsu." Under the furiten rule, a player cannot win by ron on a tile in their own discard pond, so the opponent cannot ron on 5 Man. Therefore, on turn 1, discard the 5 Man from your hand.

Once committed to defense, counting the genbutsu in your hand shows how many turns you can survive. This hand has only 1 genbutsu (the 5 Man), so from turn 2 you need other clues. Here, you can utilize the "suji" connected to that 5 Man.

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The fastest way to absorb these concepts is to put them to the test in actual matches. Play solo at your own pace against computer opponents, even with no network signal.

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Turn 2: Check Suji Based on Two-Sided Waits

In this diagram, the block of 4 Pin and 5 Pin (needing 1 tile to complete a sequence) forms a two-sided wait for 3 Pin and 6 Pin. If your own discard pond holds even 1 copy of 3 Pin or 6 Pin, your hand is furiten and you cannot ron on either. Two-sided waits link numbers spaced 3 apart, such as 1-4-7, 2-5-8, and 3-6-9; this link is called "suji."

Apply this to the opponent: if 5 Man is in their discard pond, any two-sided wait of 3-4 Man or 6-7 Man is furiten and cannot ron. Thus, with 5 Man discarded, 2 Man and 8 Man will not lose to a two-sided wait. For the earlier hand, the suji tile 2 Man becomes the discard candidate on turn 2.

• When 4 is discarded: 1 and 7 do not hit two-sided waits, because the 2-3 wait and 5-6 wait would both be furiten.
• Nakasuji: A middle tile whose outer suji tiles are both discarded, like 4 when both 1 and 7 are out, is very safe against two-sided waits.
• Caution: Suji only eliminates two-sided waits. Closed waits, single-tile waits, and Seven Pairs can still win on suji tiles.

Turn 3 Onward: Count How Many Honor Tiles Are Visible

After genbutsu and suji, look at honors. Honors cannot form sequences, so waits on them are mainly shapes on matching tiles, such as single-tile waits or dual pair waits. Their safety depends on how many are visible on the table. The defense order against riichi is as follows:

1. Discard genbutsu: Search your hand for tiles identical to those in the riichi caller's discard pond, and discard them.
2. Discard suji tiles: When genbutsu runs out, deduce suji from the opponent's discard pond, preferring terminal tiles like 1 or 9.
3. Discard visible honor tiles: If 3 copies of an honor tile are visible on the table and you hold the remaining one, nobody else can hold it, making it safe except against a Thirteen Orphans single wait.

This order is only a guide. An honor tile with 3 copies visible is nearly as safe as genbutsu, except against a Thirteen Orphans single wait, so you can discard it before suji. Conversely, an unseen honor tile can hit a dual pair wait if an opponent holds a pair.

In matches against people, the timer often rushes discard decisions. When you want to check genbutsu and suji without time pressure, practicing your decisions in Jankokushi, a mahjong game where you can play calmly solo against the computer, is very helpful.

When your hand is far from tenpai, choosing to defend with genbutsu and suji rather than forcing attacks avoids costly deal-ins and stabilizes your game.

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Why not test your knowledge of yaku and riichi in Jankokushi, the mahjong RPG where you sit at tables with Three Kingdoms figures on a quest across the land?

Free to play. Contains ads. No in-app purchases.