Taiwanese Mahjong · 1 tai

Half Exposed (Ban Qiu Ren) in Taiwanese Mahjong: Tai, Examples and Odds

In Taiwanese mahjong, half exposed (半求人, ban qiu ren — "half asking others", listed in the tai table as "All claimed, self-drawn") is worth 1 tai: all five sets are chowed, punged or exposed kongs, one tile is left in your hand for a pair wait, and you self-draw the winning tile. The self-draw's 1 tai counts too, so a half exposed hand is at least 2 tai. The same hand won on a discard is All Exposed.

The rules for Half Exposed

• All five sets are claimed chows, pungs or exposed (or added) kongs; one tile left in hand
• The winning tile is self-drawn; on a discard it's All Exposed
• A concealed kong rules it out: you drew those four tiles yourself, so not every set was "asked for"
• It's always a pair wait, so there's no extra single wait

Half Exposed vs All Exposed

Half exposed totals 2 tai and all exposed 2 tai — the same number. The difference is who pays: half exposed is a self-draw, so all three pay; all exposed is paid only by the discarder. When a table says "half exposed is 2 tai", it means including the self-draw.

How Half Exposed is scored

The tai below are computed live by the same scoring code the game uses (dealer and dealer-streak tai are added on top).

Common combinations:

How it relates to other hands

• Self-Drawn: half exposed is always a self-draw, and the self-draw's 1 tai counts.
• All Exposed: the same five claimed sets won on a discard score all exposed, 2 tai.
• Single Wait: one tile left is always a pair wait; that's already part of half exposed and isn't added.
• All Pungs, Half One Suit: five punged sets are All Pungs; one suit plus honors is Half One Suit — both stack with half exposed.
• Concealed Self-Draw: the exact opposite — nothing claimed, self-drawn.

Half Exposed odds

We let four computers play 12,000 hands on this site's table (normal level); 11,677 of them ended with a win, and half exposed appeared in only 1 — far too few to give a meaningful rate.

The reason is easy to see: you need five claims, a single tile left, and then you have to draw its match yourself. The computers claim a lot, but they're usually ready and winning after two or three claims; they rarely get to five exposed sets. It's just as rare at human tables — a hand you stumble into rather than plan.

Things to watch when you get there

• Only a pair wait: with two tiles (the one you drew plus the one you held), you keep one to wait on. Keep the tile others are more likely to throw or that has more copies left in the wall.
• Almost no defence: with only two tiles to choose from, you'll often be forced to discard a dangerous tile when someone else is ready. Think twice before making the fourth and fifth claim.
• Everything is on the table: with all five sets showing, others can roughly guess your wait and won't throw it, so you'll mostly need to self-draw.

To try it, open a table of online Taiwanese mahjong — the computers play with you and count the tai for you.

Half Exposed in other mahjong styles

• Chinese Official (Guobiao) has no half exposed — only "Melded Hand" (all sets claimed, won on a discard), 6 fan (Guobiao fan list)

FAQ

How many tai is half exposed?

On this site half exposed is 1 tai, plus the self-draw's 1 tai that always comes with it — 2 tai in total.

What's the difference between half exposed and all exposed?

Both have all five sets claimed and a pair wait. Self-drawing the last tile is half exposed; winning on a discard is all exposed.

Does a concealed kong still count as half exposed?

No. A concealed kong's tiles were drawn yourself, so not every set was claimed.

Does half exposed add single wait?

No. One tile left is always a pair wait, and that's already part of half exposed.

Related hands

All Exposed 2 tai All five sets claimed and a pair wait won on a discard: 2 tai. Half exposed vs all exposed, combos, and why it's rarely worth chasing. Self-Drawn 1 tai Drawing your own winning tile — 1 tai, paid by all three opponents. Self-draw vs concealed self-draw, scoring combos and how often it happens. Single Wait 1 tai Only one tile can win — 1 tai. Edge, closed and pair waits, false single waits, and how often it happens.