Mahjong push-or-fold guide: genbutsu, suji, kabe and deciding when to defend

What is a safe tile?

A safe tile is unlikely to be ronned by a particular opponent, but the degree of safety depends on the evidence. Do not equate genbutsu, which that opponent cannot ron, with suji, which rules out only certain waits.

Danger changes with tile position, visible copies, opponents' discards and calls, and turn number. Special shapes such as thirteen orphans and seven pairs also differ from four sets and a pair.

Genbutsu: the first tiles to look for when defending

Genbutsu are tiles already discarded by the opponent you are watching. An opponent cannot ron when their wait includes one of their own discards, so genbutsu cannot deal into that player. If you decide to fully fold, look for genbutsu first.

Genbutsu is safe only against that opponent. If the player to your left discarded 4 characters, either of the other players can still ron it. Against two riichi players, one player's genbutsu may be dangerous to the other.

A tile discarded by someone else and passed after riichi also remains safe against the riichi player's fixed wait. An open-hand player who has not declared riichi can change their wait, so a tile that passed once may not remain safe for the rest of the hand.

With several genbutsu choices, consider future turns too. An order that preserves tiles safe against multiple players, or tiles likely to remain safe, makes continued defense easier.

What is suji?

Suji uses two-sided waits and furiten to reduce estimated danger. Remember the three number families: 1–4–7, 2–5–8 and 3–6–9.

The 1–4–7 suji family

The 2–5–8 suji family

The 3–6–9 suji family

For example, if 4 characters is safe against an opponent because of furiten, the two-sided waits formed by 23 or 56 characters would also be furiten, since they include 4 characters. This reduces the chance that 1 or 7 characters deals into those shapes. Suji protects only against some two-sided waits: it gives a reason for lower danger than non-suji, not a guarantee of safety.

Why can suji still deal in? Waits it does not rule out

Suji reasoning addresses two-sided waits. It does not rule out single-tile, double-pair, closed or seven-pairs waits.

Even with 4 characters genbutsu, 1 characters can hit a single-tile wait

It can also hit a double-pair wait on 1 characters and East

Even with 5 circles genbutsu, 13 circles can wait on 2

Kabe: use visible tiles to narrow possible waits

Kabe, or a tile wall, uses the number of visible copies to restrict the sequences an opponent can hold. Your hand, all discards, exposed sets and dora indicators all count as visible tiles.

If all four 3-character tiles are visible, an opponent cannot hold 23 characters. They therefore cannot wait on 1 characters through that two-sided shape, reducing its danger against two-sided waits.

Count the tiles needed to form the opponent's wait, not just the tile you want to discard. Kabe mainly narrows sequence waits; it does not rule out single-tile or double-pair waits.

What is no-chance?

No-chance means all four copies of a tile needed for a particular two-sided wait are visible. With all four 3-character tiles visible, the opponent cannot hold 23 characters, so 1 characters cannot hit that two-sided wait.

No-chance often provides stronger evidence than suji, but it is not genbutsu. When fully folding, generally use available genbutsu first.

What is one-chance?

One-chance means three copies of the required tile are visible. The opponent can still form the two-sided wait if they hold the last copy, so it is less safe than no-chance.

You do not know whether the last unseen copy is in the wall or the opponent's hand. Especially late, when hands are developed, do not dismiss the possibility that it is in use. Treat one-chance as one clue when comparing safety without genbutsu, and do not overtrust it.

How safe are honors?

Honors form no sequences, so they have no suji relationships. Assess safety from visible copies, value-honor status and whether the opponent could have seven pairs or thirteen orphans.

If no copy of a value honor is public, an opponent may hold a pair or concealed triplet of that dragon, seat wind or round wind. Conversely, if three copies are visible outside your hand and you hold the fourth, it cannot be used against you in a standard hand or seven pairs. Exceptions such as thirteen orphans remain.

What is full defense (betaori)?

Full defense abandons your own win and prioritizes avoiding a deal-in. Continue choosing safer tiles even if that breaks tenpai or a valuable hand.

After deciding to fold, discarding suji or non-suji first to preserve your shape produces halfhearted defense. Start with genbutsu and plan a discard order that preserves safe choices for later turns. Think beyond one safe discard: how many turns can you survive until the hand ends?

What is maneuvering (mawashiuchi)?

Mawashiuchi means discarding relatively safe tiles while preserving a route back to tenpai or a win. Your choices are not limited to pushing directly or folding completely.

It can work with a valuable one-shanten hand if a genbutsu discard preserves shanten, or if you can hold dangerous tiles and wait for safe improvements. But if safe discards barely advance the hand, or winning still requires passing several dangerous tiles, fully folding may be better than forcing a comeback.

Can you push against riichi whenever you are in tenpai?

Tenpai increases the value of pushing. A high-value, good-wait hand that needs only one dangerous tile to pass is especially attractive.

Tenpai is not an automatic reason to push. A 1,000-point poor wait, almost no unseen winning tiles, several non-suji discards against dealer riichi, or few remaining turns can make breaking tenpai and folding the better choice.

How far should you push at one-shanten?

One-shanten is one step from tenpai. It looks close, but you still need to reach tenpai and then obtain a winning tile, so the gap from tenpai is substantial.

Consider pushing or maneuvering with many good-wait improvements, high potential value, many draws left, or a route to tenpai through safe discards. Lean toward folding if a cheap, poor-shape hand requires several dangerous discards. Check which tiles reach tenpai and the waits afterward, not just the label “one-shanten.”

Should you normally fold at two-shanten or farther?

At two-shanten or farther, the hand needs several improvements before it can win. From the middle of a hand onward against riichi, the chance of your own win is usually low compared with the risk of dealing in first, so defense is generally favored.

Placement conditions can still justify pushing a distant hand—for example, last place in the final round with no way to improve placement except winning. Distinguish ordinary expected value from the result you specifically need.

How does hand value affect the decision?

Higher-value hands offer a larger reward and are easier to justify pushing. Passing several dangerous tiles against the dealer for 1,000 points differs greatly from risking one tile with good-wait mangan tenpai, even at the same deal-in probability.

Even an expensive two-shanten hand is far from winning late in the round. Conversely, a 1,000-point final-round win that improves placement can be very valuable. Consider the score's effect on placement, not only its size.

Good and poor waits change the decision

A two-sided wait offers at most two types and eight winning tiles. Closed and edge waits offer at most one type and four copies, fewer after subtracting visible tiles. A double-pair wait has two types but uses two copies of each already, leaving at most four.

Ask whether the hand is likely to win, not merely whether it is in tenpai. Many visible winning tiles weaken even a good wait. A poor wait can still justify pushing if useful copies seem likely to remain and the hand is valuable.

How does turn number affect the decision?

Early in a hand, many draws remain to improve and win. In the middle, compare hand value with danger. Late in the hand, fewer chances remain, so pushing dangerous tiles from outside tenpai is often less worthwhile.

Late, tenpai payments at an exhaustive draw also matter. Maintaining tenpai safely has value, but avoiding a noten payment may not justify a large deal-in risk. Weigh remaining draws, the number of dangerous tiles to pass and the possible loss.

Dealer riichi versus non-dealer riichi

Dealer wins score more, so dealing into dealer riichi generally costs more. A dealer win also repeats the dealer turn, affecting the remaining game. With the same hand and dangerous tile, assess dealer riichi more cautiously.

Non-dealer riichi is relatively easier to push against, but visible dora and other information may indicate high value. Do not use a rigid “fold against dealer, push against non-dealer” rule; compare the opponent's value with your own winning value.

Your own dealer status matters too

As dealer, your wins score more and let you retain the dealer turn. A valuable good-wait tenpai therefore often offers more reason to attack than it would as a non-dealer.

Being dealer does not justify every push. A cheap two-shanten hand or late poor-shape one-shanten hand may still warrant folding if it requires several non-suji discards against an apparently expensive riichi.

How to defend against two or three riichi players

With multiple riichi players, a tile safe against one may threaten another. First look for common genbutsu safe against everyone. If none exist, assess each opponent separately using genbutsu, suji and kabe.

A non-suji discard can now deal into more than one player, raising the risk. Even in tenpai, cheap hands and poor waits need a stronger reason to push. If safe tiles run out, also consider which opponent's win would hurt your position most.

Push-or-fold decisions against open hands

An open-hand player may also be in tenpai. Estimate value and possible waits from visible information: the chosen suit and honors for a flush, potential pairs for toitoi, or the last value honor when a yaku depends on a later call.

A riichi player's wait is generally fixed, while an open-hand player can change shape and wait with each hand discard. A tile that passed once may no longer be safe. Reassess hand discards versus drawn-tile discards, calls, dora and unseen counts each turn.

The final round changes the priorities

In the final round, the effect on final placement matters more than the raw winning score. In last place, a win that improves placement can justify extra risk. In first place, if a deal-in would surrender the lead, defense becomes more valuable.

Check your placement after a win, a deal-in and an opponent's tsumo. With uma and oka, also consider the value of moving up or down one place.

The same dangerous tile can call for a different decision

Compare situations where you would discard a 4 characters that has not passed against the opponent.

Good-wait mangan tenpai against non-dealer riichi

Mid-hand, with good-wait mangan tenpai against a non-dealer, lean toward pushing if passing one 4 characters maintains the wait. You are close to winning and the reward is substantial.

Poor-wait 1,000-point tenpai against dealer riichi

With a 1,000-point poor wait against the dealer, lean toward folding if you must pass more non-suji tiles after 4 characters. The possible loss is large relative to the reward.

Two-shanten late in the hand

Late, far from winning and with safe tiles available, generally favor folding. Few draws remain, and even if 4 characters passes, the hand cannot immediately compete.

Final-round placement conditions

In last place needing a win, lean toward more aggression; in first place where a deal-in loses the lead, favor more defense. The same 4-character discard can warrant opposite decisions in different situations.

A push-or-fold decision is not permanent

Pushing one tile does not commit you to pushing every later tile. Reassess if another player declares riichi, winning tiles become visible, several more dangerous discards are needed, or your hand's value falls.

Conversely, maneuvering through safe discards may restore a valuable good-wait tenpai and justify switching to attack. Update the decision on every turn, not just once per hand.

Common beginner push-or-fold mistakes

• Always folding against riichi: Giving up even high-value good-wait tenpai loses winning opportunities.
• Always pushing in tenpai: Cheap hands, poor waits and dealer riichi can favor defense.
• Treating suji as guaranteed safe: It rules out only some two-sided waits.
• Overtrusting one-chance: The opponent may be using the last copy.
• Treating one player's genbutsu as safe against everyone: Genbutsu is opponent-specific.
• Not counting your hand for kabe: Count every tile visible to you.
• Treating dealer and non-dealer identically: Dealing into the dealer usually costs more.
• Ignoring placement: In the final round, placement changes matter more than raw hand value.
• Continuing to push because you already pushed: Update the conditions each turn.
• Judging only by the deal-in result: Review using information available at the decision.

What to record for a push-or-fold review

For a difficult decision, record the evidence, not just the outcome.

Use game logs to review information available at the discard. Across your overall results, compare deal-in rate, win rate, average hand value and average placement.