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FAQ #22. Chinese Official Scoring Explained
The most frequently asked questions about Chinese Official mah-jongg concern the scoring. Especially, newcomers to this variant ask about which scoring patterns (fan) may or may not be combined. This FAQ assumes that the reader is already aware of the basics of Chinese Official scoring:
There are other books besides those pictured above, in a variety of languages. See FAQ 3.
When scoring a hand, points for numerous scoring elements (fan) may be added to arrive at the hand's final score. The rules permit some latitude in this matter, but the rules do prohibit including certain combinations of scoring elements.
Depending on which rulebook the player is using, some permissible and prohibited inclusions may be already noted and documented. Most books are woefully inadequate in providing complete information about what may and may not be included when adding points.
The term "set" is used herein to refer to a pung, chow, kong, or pair. In case it helps some readers understand the concept of "sets" in mah-jongg, consider: most mah-jongg hands are comprised of sets or groupings of tiles. (Exceptions: Thirteen Orphans and the two Knitted & Honors hands, which are comprised of particular single tiles rather than sets or groupings of tiles.)

Here's How It Works
When scoring a hand...
Step 1.
The usual practice is to begin by deciding what is to be your main scoring element (usually the highest-scoring element), although it isn't strictly necessary to declare what your main scoring element is - it's just a starting point.
Step 2. Then combine any other scoring elements which are not inevitably included in that main scoring element. (Note: one way to look at it is to combine elements in decreasing numbers of sets. In practice, you can usually add any and all scoring elements that use all the sets, all the tiles, or four sets first, then add two- or three-set scoring elements. Lastly, you would add scoring elements based on concealment and/or how the winning tile had been obtained.)
Step 3. Be mindful of the "combine-just-once" principle. Having combined sets to form your main scoring element, any sets not used in that main element may be combined only once, with no more than one set that has already been used to form the main element, to form additional scoring elements. The player is permitted to try differently ordering the combinations to achieve extra points, but it rarely works out that higher scores can be obtained by doing so. There are other prohibited combinations as well. Examples are given below.
In following the steps above, certain rules apply. The following is based on the Chinese-language book, CHINESE MAHJONG COMPETITION RULES ("CMCR"), published by People's Sports Publishing House in 1998 (ISBN 7-5009-1630-2/G - 1529). Pages 29-30.
10.1.5. Principles for Scoring the Hand
The scoring of a completed hand is based on the table of scoring elements provided in the rule book. When a player completes the hand, the player shall identify the primary scoring element first, then add other scoring elements that are not inevitably related to, or derived from, the primary scoring element or one another. In calculating the hand's score, the following principles must be observed.
10.1.5.1. Prohibition against implied inclusions
When a high-scoring pattern cannot be made without also making a lesser pattern, you cannot claim both the high-scoring pattern and the low-scoring pattern. Sometimes referred to as the "non-repeating principle" or the "non-implied principle."
10.1.5.2. Prohibition against separation
Once some sets have been combined to create a particular scoring element, you may not "separate" the tiles of those sets and re-organize them into other sets to form a different scoring element. Sometimes referred to as the "non-separation principle."
10.1.5.3. Prohibition against identical patterns
Once you've used a set to form a particular 2- or 3-set pattern, you can't use the same set to form an identical pattern with another set. Sometimes referred to as the "non-identical principle."
10.1.5.4. Freedom of choice principle
If a set can be used to form a low-scoring pattern or a high-scoring pattern, you are free to claim the higher-scoring pattern. Sometimes referred to as the "high-versus-low principle."
10.1.5.5. Prohibition against repetitive set usage ("combine-just-once") Once two or three sets have been combined for a scoring pattern, any other remaining sets in the hand may be combined only once with an already-scored set, when creating additional scoring patterns. Sometimes referred to as the "assessment-once principle." Note that this principle especially affects combinations of chows-based patterns.
Examples
10.1.5.1. Prohibition against implied inclusions. When a particular scoring combination cannot possibly be made without also including another (lesser, inevitable) scoring element, the lesser element is said to be "implied," thus it is not permitted to combine the two (to add extra points). For instance, the hand "All Even" cannot be made with chows or terminals or honors (it can only be made with pungs of even numbered suit tiles), therefore it is not permitted to combine the points for "All Even" and the points for "All Pungs" or "All Simples" or "No Honors. "All Even" is worth 24 points; the points for those other attributes are "implied" (already included) in the 24 points.
For another example, it would not be permitted to combine both "half flush" (also called "clean") and "one voided suit."
10.1.5.2. Prohibition against separation. If you have 111222333 in one suit, you can either call that three pungs or three chows. You can't claim points for calling it chows, then claim additional points for calling it pungs.
10.1.5.3. Prohibition against identical patterns. For instance, if you have 123B 456B 456B, you can't say that's two short straights (using the 123B twice to form two identical patterns).
Another example.

Last example.

10.1.5.4. Freedom of choice principle. For instance, if you have 123 456 789 all in one suit, it makes sense to claim Pure Straight (kwa leung in Chinese - Pure Dragon), rather than Short Straight. You can't have both, so claim the more valuable.
10.1.5.5. Prohibition against repetitive set usage ("combine-just-once"). While the above four principles are well understood and accepted by new players, this rule (which I used to call "the exclusionary rule") is sometimes a source of vexation and confusion. Consider this Mixed Straight hand:


234C 567C are combined to form a Short Straight. 234D can be combined with 234C to make a Mixed Double Chow. Then the remaining 567D may be combined either with 234D to make a second Short Straight or with 567C to make a second Mixed Double Chow.
234C 234D are combined to form Mixed Double Chow. 567C may be combined with 234C to form a Short Straight. Then the remaining 567D may be combined either with 567C to form a second Mixed Double Chow or with 234D to make a second Short Straight.
234C 567C are combined to form Short Straight. 234D 567D are combined to form a second Short Straight. Because of the wording of the Combine-Just-Once rule, you might be challenged if you then try to use one already-used set with another already-used set to form a Mixed Double Chow. Thus it might be your best bet to go with A or B instead.
Scoring the above hand, you get All Chows (2) and All Simples (2), then you can add any three of these four: Mixed Double Chow (1), Mixed Double Chow (1), Short Straight (1), and Short Straight (1). That makes only seven points - not enough to go out. You'll need to self-pick, go out on a unique wait, keep your hand concealed, or win on the last tile of its kind in order to get at least one more point to meet the minimum.
To recap: start by choosing your Primary Scoring Element, usually the highest-scoring element (often encompassing all the tiles or sets of the hand), as a starting point.
In the past couple of years, I've gone back and forth numerous times on how to describe this process (which I formerly referred to as "the exclusionary rule"). The more I have learned (the more different translations and interpretations of the original Chinese rules I've heard or seen), the more I see that my original statement of rule 10.1.5.5. appears to have been correct:
And this has been confirmed by the analysis done by Per Starbäck in May of 2008 (see http://starback.se/mj/beyond/). *Note: "sets" in this sentence are chows.
Note:
A controversy about the combine-just-once rule (10.1.5.5) is discussed in Column 229 and again in Column 255.
UPDATE: The controversy has been resolved! See Column 259.
World Champion Mai Hatsune and fellow Japanese champion player Takunori Kajimoto have written the definitive strategy guide to Mahjong Competition Rules. It's been translated into English and is at http://museum.takeshobo.co.jp/kokusai/index.html.
To practice your MCR strategy, join www.tilehog.net.
Many thanks to: (1) Ryan Morris (photo above) for his help in understanding the combine-just-once principle before any translations existed,
and (2) to Cofa Tsui for his translation of section 10.1.5 of the CMCR. Go to www.iMahjong.com and click General Introduction > Archives > Topic #208. In his article, Cofa refutes wording that used to exist in this FAQ originally. Changes that have been made since then were made thanks to...
(3) Larsen Chung, who also translated section 10.1.5, on the Mah-Jongg Q&A Bulletin Board,
and thanks also to (4) "ithinc" who also contributed, and to Mr. Wang Yingfu of the World Mah-Jong Championship technical committee.
Those tricky "knitted" thingies in MCR (CO)
>From: "Paula Langer" [psaltlang at hotmail]
>To: mj
>Subject: Mah-Jongg Q+A
>Date: Mon, 25 Dec 2006 19:25:32 -0200
>My mah-jongg question or comment is:Is the Knitted tiles worth 12
>points in
>Chinese Official considered a chow set and are we allowed toclaim a
>discarded tile and meld the set?
>Psaltlang at yahoo
Hello Paula,
First, I gotta say, what's the deal with the timestamp on your email? It's dated last Christmas, yet I just received it now. Maybe somebody needs to adjust your computer's clock. May as well wait until tomorrow (given the early Daylight Savings Time bug). Anyway, as to your question. This is addressed in my upcoming book, by the way (don't hold your breath, it doesn't come out until June).
Is the Knitted tiles ... considered a chow set and are we allowed toclaim a
>discarded tile and meld the set?
Yes and no. A hand comprised of three knitted SETS (147 or 258, for example) IS considered a "special sort of chow" hand -- but special rules apply. A knitted set may NOT be melded. And neither may a knitted chow.

© 2005-2008 Tom Sloper. All rights reserved. May not be re-published without written permission of the author.
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