FAQ

What is a Chow hand / No-points hand?

Patterns based on a hand consisting of four Chows and a pair are probably the most complex scoring patterns in Mah Jong. Four Winds supports numerous variations of hands based on four Chows. The reason for the variety is in adaptation of traditional patterns in rules with a different scoring system: accordingly, a single pattern may be interpreted slightly differently in order to make the scoring more balanced in the context of new rules.

The classical pattern called No-points hand (Ch. ping hou, Jap. pin fu) serves as an excellent example to illustrate how a basically very simple concept becomes complex as it is included in rules which apply scoring that differs from the originating rules.

No-points hand the classical interpretation

In classical Mah Jong all Pungs and Kongs, whether concealed or melded, suits or honors, score a certain amount of basic points (jap. fu). In addition, a pair of Dragons or a value Wind (player's own Wind or Wind of the Round) also scores a minor bonus. Chows, however, are valueless by itself. So in classical Mah Jong a hand with four Chows normally gets scores only for winning (traditionally 10 or 20 points), and possibly few extra points for a value pair. It can receive bonus points also for special ways of going out (self-drawn, on a pair or a one-chance Chow). In addition, it can score bonus doubles for being e.g. One suit only

As Chows are so easy to collect, a Chow hand itself is not given in classical rules a merit unless it meets specific requirements. In classical Chinese Mah Jong it was only required that a Chow hand must not contain a pair that produces points. However, it seems that some versions of the classical rules used a stricter interpretation, which is still applied in Japanese Mah Jong (both classical and modern), and sometimes also in modern Chinese game, even if the latter no longer uses the point (fu) unit in scoring assignments. According to this interpretation a Chow hand must not score anything in point (fu) units, excepting the basic 20 points/fu for winning (and, if applicable, a bonus of 10 points/fu for being a concealed hand with discarded winning tile) hence the name No-points hand, Ch. ping huo, Jap. pin-fu. Note that bonus doubles are always allowed, e.g., a "No points hand" can receive doubles for being composed of One suit only

Firstly, "no-points" means that the pair must be valueless (since having a pair of Dragons / own Wind / Wind of the round is worth 2 points/fu). Secondly, since the classical rules give 2 bonus points (fu) for going out self-drawn, on a pair or a one-chance Chow, these special cases, if they score a bonus in points/fu unit (or if the Traditional interpretation option is checked, which applies the same restriction in rules that do not specify scoring for the mentioned patterns) are often not allowed in a No-points hand. A common variation is to accept these special ways of going out but without giving bonus for them  the pair, however, must always be valueless. Another common variation (in Japanese Mah Jong) forbids all special ways of going out that score bonus points except going out on a fully concealed hand (self-drawn winning tile) no bonus points for going out on a self-drawn tile are paid in this case (note that this exception allows using the self-drawn tile only with a concealed hand, not if the hand already contains melded sets).

As the concept of No-points hand was later adopted in other versions of Mah Jong, often without proper understanding of the underlying scoring system, several variations evolved. The common aspect in all variations is that a hand consisting of four Chows and a pair must meet certain special requirements in order to deserve scoring.

Examples of variations of patterns based on four Chows
The table below describes how a pattern based on four Chows and a pair is interpreted in different rules:
Rules Pattern (in Four Winds) Options (No = Not applied) Description of restrictions
Chinese Classical / European Classical Chow hand Out on Chow (No); No value pairs (Yes); No Honors (No) The only restriction is that the pair must not be composed of pairs that produce points, which in the Chinese Classical rules are Dragons, player's own Wind or Wind of the Round. 
Hong Kong / Chinese New Style / Wilmington Advanced Chow hand Out on Chow (No); No value pairs (No); No Honors (No) The only restriction is that the pair must not be composed of traditional value pairs, i.e., Dragons, player's own Wind or Wind of the Round (note that these rules do not actually assign scoring for these pairs).
Chinese Official / WMPA Chow hand Out on Chow (No); No value pairs (No); No Honors (Yes) Only restriction is that the pair must not be composed of honors (dragons or any winds).
Taiwanese 16-Tiles Mah Jong Chow hand Out on Chow (No); No value pairs (No); No Honors (Yes) Only restriction is that the pair must not be composed of honors (dragons or any winds).
Grand Chow hand Out on Chow (No); No value pairs (No); No Flowers (Yes); No Honors (Yes) Only restriction is that the pair must not be composed of honors (dragons or any winds), and that the hand contains no Flowers/Seasons.
Japanese Classical
(also, many Western versions based  on classical Mah Jong)
No-points hand  Allow special ways of going out (No); Allow fully concealed hand (No); No Honors (No); Traditional interpretation (No) Must not score anything in point (fu) units, excepting the basic 20 points for winning (and possibly 10 points for a concealed hand, winning tile being a discard). Practical implications are: the winning tile must be a discard, the pair cannot be composed of Dragons, player's own Wind or Wind of the Round, and the completing set must not be a pair or a one-chance Chow.
American Classical
(also used in some Japanese versions)
No-points hand  Allow special ways of going out (Yes); Allow fully concealed hand (No); No Honors (No); Traditional interpretation (No) Must not score anything in point (fu) units, excepting the basic 20 points for winning. This means that a hand cannot contain a pair that has a scoring value. On the other hand, special ways of going out going out on a pair or going out on a one-chance Chow are allowed, but points for these are ignored when calculating the final score.
Japanese Modern No-points hand Allow special ways of going out (No); Allow fully concealed hand (Yes); No Honors (No); Traditional interpretation (No) Basically the same as No-points hand in Japanese Classical, but going out with a fully concealed hand (self-drawn winning tile) is allowed; the extra scoring worth 2 fu is forfeited. Separate scoring for having a melded (10 fu) or concealed (1 han) Chow hand ('concealed' meaning that the winning tile can be either self-drawn or a discard).
Korean Style No-points hand Allow special ways of going out (No); Allow fully concealed hand (No); No Honors (No); Traditional interpretation (Yes) Basically the same as No-points hand in Japanese Classical, though the idea of having no point units is naturally not relevant in the rules which are not based on a point-double (or fu-han) scoring system. The Traditional interpretation option specifies that the hand must not go out on a self-drawn tile, and must be completed with a multiple-chance Chow. The basic requirement for non-valuable pair is applied, as well.
Mahjong Masters Million  Chow hand Out on Chow (No); No value pairs (No); No Honors (No) Scoring only for having a concealed Chow hand (winning tile can be a discard)
Internet Mahjong Server Chow hand Out on Chow (No); No value pairs (No); No Honors (No) No restrictions; separate scoring for having a melded (1 faan) or concealed (2 faan) Chow hand ('concealed' meaning that the winning tile can be either self-drawn or a discard).
Alan's Zung Jung Chow hand Out on Chow (No); No value pairs (No); No Honors (No) No restrictions; always scores 5 points.
Dutch League Rules Chow hand Out on Chow (No); No value pairs (No); No Honors (No) No restrictions.
Australian Modern  Chow hand Out on Chow (No); No value pairs (Yes); No Honors (No) More than 1 Chow is allowed in a fully concealed hand only. In addition, the pair must not be composed of Dragons, player's own Wind or Wind of the Round. 
American Modern / British n/a n/a Only 1 Chow is allowed in the winning hand (unless it scores a limit)
French / Italian n/a n/a No scoring for hands based on four Chows.

Note: In modern Chinese versions of Mah Jong there are often numerous patterns based on four Chows (e.g., Terminal Chows twice, Two identical Chows twice), but these are all relatively difficult hands to collect and cannot be compared with the concept of No-points hand.

Chicken hand

In modern Chinese Mah Jong there is a concept called Chicken hand, which is sometimes confused with No-points hand. The concepts are quite different, though: a Chow hand normally scores 1 faan in modern Chinese Mah Jong, but can earn additional faans for several other patterns. A chicken hand, on the other hand, is a hand which has no other scoring value (certain exceptions are often allowed for special cases like Flowers/Seasons or Dora tiles) , and normally consists of mixed sets (Chows and Pungs). In highly pattern oriented versions of Chinese Mah Jong, Chicken hand is sometimes rewarded with 1 faan, or even more.

Related topics:
Scores for patterns based on Chows
Scores for patterns based on the whole hand

Maximum number of Chows
Exceptions