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By Tom Sloper
July 12, 2015

Column #639

American Mah Jongg (National Mah Jongg League rules). I've written about the "window of opportunity" before (column 458, July 2010). But my definition has since expanded. In explaining the League's rule, I referred to official sources only: the official rulebook and several yearly newsletters. Thence I came up with this (FAQ 19-C):

You see that although there is just one thing that opens the window, there are four things that can close the window. Actually, there may be even more! Let's examine each of those events a little more closely.

Opening the window. When a player discards a tile, the window of opportunity to claim that discard opens.

Closing the window. There are four (or, arguably, more) things that can close the window:

Next player racks. The word "racks" is blue and underlined, above, because that term has come into question many times (so I wrote FAQ 19-AD to define it). A picked tile is "racked" when it is placed among the player's concealed tiles. Frequent sticky question: "what if someone else calls for the discard just as the next in turn is racking?" In that sticky case, you have to consider whether the picker picked and racked a little too quickly, or if the caller delayed just a hair too long. If a picker is pausing just a beat before picking, then she's allowed enough time for another player to call the live discard. Someone who doesn't speak until a reasonable-speed picker is in the act of racking has probably taken a hair too long deciding to call the discard, and is too late. (Of interest: the Chinese rule is that a caller has a 3-second window.)

Next player discards. When the next in line picks a tile from the wall and discards it (without racking, which is permissible), the window has closed on the previous discard. A window now opens on the new discard.

Next player declares mah-jongg. When the next in line picks a tile from the wall, looks at it, and declares mah-jongg, the window is closed.

Next player exchanges a joker. When the next in line picks a tile from the wall and uses it to redeem a joker, the window is closed.

Someone claims the discard, but next in turn supersedes the claim. One could say that someone claiming the discard is a fifth way to close the window - but actually, if that someone was not next in turn, the window is still not necessarily closed! The next in line from the discarder can still claim the discard (as long as the first claimant has not yet racked it).

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Need rules for American mah-jongg? Tom Sloper's book, The Red Dragon & The West Wind, is the most comprehensive book about the American game, including official rules not included in the official rulebook. AND see FAQ 19 for fine points of the American rules (and commonly misunderstood rules). AND get the official rulebook from the NMJL (see FAQ 3).

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