Designing Four Seas Intermediate, Part II: Hand-Building and Winning Requirements

See Four Seas Mahjong (Intermediate Edition): Entertaining Hand-Building Rules, Four Seas Mahjong Intermediate Edition: Rules Explained, and Designing Four Seas Intermediate, Part I: Scoring Patterns.

Hand-building rules should encourage players to construct beautiful, large hands. Their foundation is therefore a sufficient variety of aesthetically appealing, relatively independent pattern families covering as many starting hands as possible. Designing Four Seas Intermediate, Part I: Scoring Patterns described eighteen main routes: six chow, six pung, and six whole-hand families. Each includes small, intermediate, and large patterns, reflecting both progression from small to large hands and a beginner's movement from easier to harder construction.

Minimum winning requirements

Alongside varied pattern families, a higher minimum score is needed to prevent small-hand racing. As Two Tensions in Hand-Building Mahjong, Part I: Building Hands and Racing to Win discussed, most current rules reward the player who completes a winning hand. All such mahjong is therefore racing mahjong. However high the minimum is set, players still pursue the easiest qualifying hands: those just above the threshold. Different rules simply race for hands of different difficulty.

Hand-building mahjong can also be racing mahjong. Its design should encourage players to build hands while racing to win, so that following hand-building principles yields the greatest return. While players pursue victory, their hands should display the beauty of large patterns, and their attack and defense should express an understanding of construction and the situation. That is the goal.

Four Seas is also racing mahjong, but can encourage hand-building within that race. The minimum should lie below the main-route patterns, allowing them to qualify. However many routes a ruleset offers, many starting hands will suit none of them. To preserve freedom rather than force every hand into a main route, small-pattern combinations should also be allowed to qualify, provided their difficulty is comparable to that of a main-route hand.

Four Seas main-route patterns score thirty to forty points, while small patterns score five to ten. Twenty is therefore an appropriate minimum. Mixed One-Suit, All Triplets, Mixed Outside Hand, Three Similar Sequences, and similar main patterns qualify directly, while combinations of five- and ten-point patterns can also reach twenty.

Category	ID	Yaku	Points	Definition
Suit	A.1	All Types	20	A winning hand composed of suited tiles from all three suits, wind tiles, and dragon tiles
	A.2	Mixed One-Suit	30	A winning hand composed of tiles from one suit and honor tiles
	A.3	Pure One-Suit	60	A winning hand composed entirely of tiles from one suit
Pattern	B.a1	All Sequences	5	A winning hand composed of four sequences and a pair
	B.a2	All Triplets	30	A winning hand composed of four triplets and a pair
	B.b1	Seven Pairs	60	A winning hand composed of seven pairs
	B.c1	All Unrelated	30	A special hand composed of single tiles from three suits in 147, 258, and 369 patterns, together with honor tiles
	B.c2	Seven All Unrelated	40	A hand composed of one of each of the seven honor tiles and seven suited tiles in a 147, 258, or 369 pattern, with no pair
	B.c3	Five Honors and Knitted Straight	60	A hand composed of a complete knitted straight (147, 258, 369 across three suits) and five distinct honor tiles, with no pair
	B.c4	Thirteen Orphans	160	A hand composed of 1 and 9 of each suit, all seven honor tiles, plus one duplicate tile as the pair
Number terminal	C1.1	All Simples	5	A winning hand with no terminals or honor tiles
	C1.2	Mixed Outside Hand	30	Each set or pair contains at least one terminal or honor tile
	C1.3	Pure Outside Hand	40	Each set or pair contains at least one terminal tile
	C1.4	All Terminals and Honors	80	Each set or pair is composed only of terminals and honor tiles. Already includes Mixed Odds; Must be combined with All Triplets or Seven Pairs
Number linked	C2.1	Mixed Linked	20	Each set or pair contains a specific number, or is composed of honor tiles
	C2.2	All Linked	40	Each set or pair contains a specific number
	C2.3	All Symmetric	80	Each set or pair contains a specific number, and in sequences this number is the middle tile
Quad	D.1	One Quad	10	One Quad
	D.2	Two Quads	30	Two Quads
	D.3	Three Quads	120	Three Quads
Honor Dragon	E1.1	Value Honor	10	A triplet of seat wind or dragon tiles
	E1.2	Little Three Dragons	80	Two dragon triplets and a pair of the third dragon
	E1.3	Big Three Dragons	160	Three dragon triplets
Honor wind	E2.1	Little Three Winds	30	Two wind triplets and a pair of the third wind
	E2.2	Big Three Winds	80	Three wind triplets
One-Suit identical Seq	F1.1	Two Identical Sequences	10	Two identical sequences in one suit
	F1.2	Two Identical Sequences Twice	80	Two sets of identical sequences. Already includes All Sequences
	F1.3	Three Identical Sequences	120	Three identical sequences in one suit
One-Suit shifted seq	F2.1	Two Shifted Sequences	5	Two shifted sequences in one suit (differing by one number)
	F2.2	Two Shifted Sequences Twice	60	Two sets of shifted sequences. Already includes All Sequences
	F2.3	Three Shifted Sequences	60	Three shifted sequences in one suit (each increasing by one number)
	F2.4	Four Shifted Sequences	160	Four shifted sequences in one suit (each increasing by one number). Already includes All Sequences and Half Straight
One-Suit straight	F3.a1	Two Terminal Sequences	5	Sequences 123 and 789 in the same suit
	F3.a2	Pure Straight	40	Sequences 123, 456, and 789 in the same suit
	F3.a3	Golden Bridge	120	Sequences 123, 345, 567, and 789 in the same suit. Already includes All Sequences
	F3.b1	Half Straight	5	Two sequences formed by six consecutive tiles in one suit
	F3.b2	Half Straight Twice	40	Two sets of Half Straight. Already includes All Sequences
	F3.b3	Mirrored Half Straight	60	Two identical Half Straight sets in two different suits. Already includes All Sequences, Two Similar Sequences and Mirrored Sequences
Three-Suit identical seq/trip	G1.a1	Two Similar Sequences	5	Two identical sequences in two different suits
	G1.a2	Three Similar Sequences	30	Three identical sequences in three different suits
	G1.c1	Mirrored Sequences	40	Two sets of Two Similar Sequences across two suits. Already includes All Sequences
consec seq/trip	G2.a1	Assorted Straight	20	Sequences 123, 456, and 789 across three different suits
chance turn	H1.1	Last Tile Draw	20	Winning by self-draw on the last tile of the wall
	H1.2	Last Tile Claim	20	Winning on the last discarded tile
	H1.3	Blessing of Man	60	A non-dealer starts in wait with 13 tiles and wins on another player’s discard before drawing, counted as a self-draw win
	H1.4	Blessing of Earth	120	A non-dealer starts in wait with 13 tiles and wins on the first self-drawn tile
	H1.5	Blessing of Heaven	160	The dealer wins immediately with the initial 14-tile hand
chance Kong	H2.1	Robbing a Kong	20	Winning by robbing a kong (claiming a tile from a declared kong)
	H2.2	Win by Kong Replacement	20	Winning on a replacement tile drawn after declaring a kong

Combining small patterns

Below twenty points, Intermediate has five- and ten-point patterns. The five-point patterns include two whole-hand patterns, All Sequences and All Simples, and four two-chow combinations: the easier Two Similar Sequences and Half Straight, and the harder Two Terminal Sequences and Two Shifted Sequences. The ten-point Two Identical Sequences also uses two chows and can be considered alongside them. The approximate ratio of combination counts for the four chow patterns is 7:4:1:1, with Two Identical Sequences at about 0.3 on that scale. Any four of the six five-point patterns total twenty. Since the small chow patterns each use two chows, however, a four-chow hand supports at most three such combinations, while necessarily also satisfying All Sequences.

The simplest qualifying combinations are therefore: 1. All Sequences + All Simples + Two Similar Sequences + Half Straight; 2. All Sequences + All Simples + Two Similar Sequences twice, without forming Mirrored Sequences; 3. All Sequences + Two Similar Sequences + Half Straight + either Two Terminal Sequences or Two Shifted Sequences; and 4. All Sequences + All Simples + Two Identical Sequences. Since identical and shifted chows can transform into one another, there is a useful two-sided-wait technique: one end makes Two Identical Sequences, while the other makes Two Shifted Sequences plus Two Similar Sequences. Both ends supply ten points, which combine with All Sequences and All Simples to qualify.

Apart from Two Identical Sequences, the ten-point patterns are pung-related: a kong, Value Honor, Two Similar Triplets, and Two Consecutive Triplets. Any two qualify. These ten-point patterns generally combine poorly with the five-point patterns; even All Sequences and All Simples do not easily fit pung-related patterns.

Four Seas avoids small-hand racing because qualifying through small patterns is already about as difficult as building a main-route hand. The combinations above are in the same general difficulty range as Three Similar Sequences and Assorted Straight, offering little speed advantage. Their scores are also much lower. Two Similar Sequences and Half Straight each have a higher pattern—Three Similar Sequences and Pure Straight—only one chow away, so a favorable opportunity can justify continuing to build. Small-pattern combinations in Intermediate offer similar difficulty and speed to main routes but lower scores, giving suitable hands an alternative without forcing every situation into a main route. Combining small patterns is itself another form of hand-building.

Four Seas small patterns do not inflate one another's values through accumulation as they do in some other rules. As Selecting Patterns for Hand-Building Mahjong: Beauty or Difficulty? explained, Four Seas small patterns concern the aesthetic structure of the tiles, so they constrain and exclude one another. The patterns responsible for inflated combinations are purely difficulty-based rewards such as concealment, riichi, and edge, closed, or pair waits. Their unrestricted accumulation is a major source of overrewarding across rulesets.

Self-draw and discard-win minimums

Intermediate does not simply raise Basic's minimum to twenty. It distinguishes a ten-point self-draw minimum from a twenty-point discard-win minimum, preserving freedom and supporting defense. At twenty points or more, a player may win on a discard; from ten to below twenty, only self-draw is allowed. During construction, one's main route may become blocked, or an opponent may be approaching readiness. With a uniform twenty-point minimum, a player unable to qualify would have to fold. The lower self-draw requirement allows a fortunate draw to complete a ten-point hand even when it falls short of the discard-win threshold.

This adds a defensive option. Facing an opponent's ready or large hand, a player can fold while retaining the chance to interrupt it with a small self-drawn win. Self-draw is purely luck-driven and occurs about twenty-five percent of the time, so players will still aim for a main route or a twenty-point combination, rather than deliberately build only ten points. The design thus does not encourage small-hand racing; ten points is a defensive fallback. It also gives self-draw an additional function: winning with a hand below the normal qualifying threshold.

The idea comes from regional Chinese rules. Some Guangdong and Hunan variants permit discard wins only for large hands, while small hands must be self-drawn. Those rules may allow a zero-point Chicken Hand by self-draw. Four Seas still requires ten points, maintaining a minimum and excluding unrestricted basic wins.

The value of small patterns

Separate self-draw and discard-win requirements give small patterns additional defensive value. Small patterns are stages on the way to larger ones, but also retreat options. Suppose a player building Three Similar Sequences finishes with a two-sided 1/4-bamboo wait. The 1-bamboo completes the thirty-point main pattern; the 4-bamboo gives only five-point Two Similar Sequences. With All Sequences, however, that reaches the ten-point self-draw minimum. Drawing the 4-bamboo creates a choice: persist with Three Similar Sequences or accept the smaller hand, depending on the table situation. The five points from Two Similar Sequences are essential to that option. A lower pattern is therefore a fallback within the same family, and winning small may reflect a deliberate decision to abandon a larger win.

Small-pattern selection is consequently not arbitrary. Because lower patterns serve both offense and defense, a two-meld pattern should preferably have several higher forms. The following table shows both three-meld and two-pairs-of-melds extensions. Two Dragon Pungs and other excluded two-meld patterns, including the Two Consecutive Triplets mentioned in this discussion, have only a three-meld extension.

In short, small aesthetic patterns help beginners learn, support offensive construction, combine toward the minimum, and provide defensive fallback hands. Their selection matters greatly to rule design.

Two melds	Three melds	Two pairs of melds
Two Identical Sequences	Three Identical Sequences	Two Identical Sequences Twice
Two Shifted Sequences	Three Shifted Sequences	Two Shifted Sequences Twice
Half Straight	Pure Straight	Half Straight Twice
Two Terminal Sequences	Pure Straight	Mirrored Sequences + Two Terminal Sequences × 2 (Double Terminal Chow Pairing)
Two Consecutive Triplets	Three Consecutive Triplets	Two Consecutive Triplets Twice
Two Similar Sequences	Three Similar Sequences	Mirrored Sequences
Two Similar Triplets	Three Similar Triplets	Mirrored Triplets

As noted earlier, whether a ruleset supports hand-building is not determined solely by the frequency of enormous hands, but also by the frequency of entire pattern families. More important than the result is the process. Hand-building concerns not only the size of the eventual winning hand, but also everyone's efforts to build throughout play. Only one player wins a hand. Continuing an offensive race, folding completely, or switching to a small self-drawn hand are all strategic choices. A football match's quality cannot be judged solely from its final score or number of goals; likewise, the share of large winning hands cannot alone measure hand-building. Strong attacks, combinations, stubborn defense, and quick counterattacks make the process exciting. Mahjong can similarly be an excellent contest when all four players respond to one another, build actively, and defend sensibly—even if it ends in a small win or an exhaustive draw.

Four Seas is racing mahjong that encourages hand-building, and hand-building mahjong in which players race to win.