Four Seas Mahjong Basic Rules Explained

This article explains Four Seas Mahjong (Basic Edition): Rules for Recreational Hand-Building Mahjong.

I. Scoring patterns

1. “The Golden Rooster Seizes Food”

This is an old Chinese name for Robbing a Kong, recorded in the Illustrated Mahjong Manual. The other chance patterns—Last Tile Draw, Last Tile Claim, and winning on a kong replacement tile—have four-character Chinese names. Restoring the old four-character name 金鸡夺食 makes the terminology more consistent and allows these patterns to be remembered together as “海河金花” (sea, river, golden rooster, flower). The same reasoning underlies the use of traditional names for the kong-replacement win and All Triplets.

2. Defining Blessing of Earth

The meaning of Blessing of Heaven is fairly consistent, but Blessing of Earth differs substantially across rulesets. Originally it meant a non-dealer winning on the dealer's first discard, a historical definition retained in Zung Jung. Riichi instead defines it as a non-dealer's first-turn self-draw, calling a first-turn discard win Blessing of Human. The main consideration is riichi's full discarder-payment system: under the original definition, the dealer would deal in before other players had drawn or discarded anything, with no information for defense. Making the dealer pay for such an enormous hand would be unfair.

In Four Seas Basic, Blessing of Earth encompasses both riichi's Earth and Human blessings. Their common feature is readiness from the initial thirteen tiles, followed by a win on the first incoming tile, whether drawn or discarded by another player. Heaven, Earth, and Human blessings are all pure chance patterns: a player can win without taking any action to develop the hand. Without Blessing of Human, the same tile could fail to qualify when discarded by someone else in the first turn but qualify as Blessing of Earth when self-drawn. That is inconsistent with the logic of the hand. Four Seas Basic therefore combines the two under Blessing of Earth and settles it as a self-draw, reflecting its purely fortuitous nature, like Blessing of Heaven, and removing discarder liability. Both Heaven and Earth have reduced values to fit the Basic edition's scoring scale.

3. A mnemonic for the patterns

平断杠、喜六番 — six minor patterns: All Sequences, All Simples, Kong, Two Similar Sequences, Half Straight, and Value Honor.

一对幺、三龙般 — eight main patterns. “一” covers Mixed One-Suit and Pure One-Suit; “对” covers All Triplets and Seven Pairs. The remaining cues refer to Outside Hands, Three Similar Sequences, Pure Straight, and Two Identical Sequences.

海河金花、天地和 — six chance patterns: Last Tile Draw, Last Tile Claim, Robbing a Kong, the kong-replacement win, Blessing of Heaven, and Blessing of Earth.

There are twenty patterns in total: fourteen structural patterns and six chance patterns. Among the structural patterns, six minor patterns help beginners get started, while eight main patterns represent the principal hand-building routes.

II. Pattern classification and scoring

Like Zung Jung, Four Seas uses pattern series as the basic unit of classification. Each series occupies a row in the pattern table. Its patterns share a rationale: they are either related as lower and higher forms, such as Two Similar Sequences and Three Similar Sequences, or mutually exclusive, such as All Simples and Outside Hands. Classification by series naturally replaces Chinese Official's principle of counting the higher pattern rather than its lower counterpart.

Series are grouped by their relationships into major groups and categories; the Intermediate edition also has subcategories. Four Seas has eight major groups, all represented in the Basic edition. Within the single-suit group, for example, there are categories for identical sequences, containing Two Identical Sequences, and consecutive sequences, containing Half Straight and Pure Straight. The scoring principle is “no reuse within the same category.” Each sequence, triplet, or pair in the winning hand can be used only once among series in the same category, but may be used again in different categories.

For example:

Example 1:

Two Kongs and two Value Honors: 40 points in total.

Kong and Value Honor may each be counted more than once when multiple qualifying sets are present.

Example 2:

Pure Straight, Two Identical Sequences, and All Sequences: 55 points in total.

The first 123 of characters is used three times: in Pure Straight, Two Identical Sequences, and All Sequences. The second 123 cannot combine with 456 to score Half Straight, because 456 has already been used in Pure Straight, and Pure Straight and Half Straight belong to the same category.

Example 3:

Three Similar Sequences, Two Identical Sequences, Outside Hands, and All Sequences: 75 points in total.

Similarly, the second 123 of characters cannot combine with 123 of dots or bamboo to score Two Similar Sequences. Those dot and bamboo sequences are already used in Three Similar Sequences, which belongs to the same category as Two Similar Sequences.

Example 4:

Two Half Straights, two instances of Two Similar Sequences, All Sequences, and All Simples: 30 points in total.

Each sequence is reused across Half Straight and Two Similar Sequences. This is permitted because the patterns belong to different categories. This differs from Chinese Official's restriction on repeated combination counting and is a more reasonable scoring method. Under Chinese Official, one could count either two Short Straights and one Mixed Double Chow, or one Short Straight and two Mixed Double Chows.

III. Minimum scores for winning

Four Seas Basic offers two minimum-score levels. For newcomers who have just learned mahjong's fundamentals, or regional players unfamiliar with scoring patterns, a 5-point minimum is comparable to requiring a qualifying pattern in riichi or Zung Jung. Any one of the twenty patterns is sufficient to win.

The standard minimum is 10 points. Besides the main patterns, the traditional Kong and Value Honor patterns each reach that threshold. The four easy 5-point patterns—All Sequences, All Simples, Two Similar Sequences, and Half Straight—can also qualify in any combination of two. Raising the minimum to 10 introduces the hand-building concept and adds interest, making Basic an independently enjoyable ruleset.

Players using different minimum scores can also play together. This accommodates different experience levels and lets experienced players guide beginners.

IV. Payment system

Zung Jung's approach of sharing payment for small hands while placing the burden of large hands on the discarder is an excellent design that addresses liability for large deal-ins. However, it emphasizes fixed income: the winner receives the same amount for self-draw and discard wins. This is not necessarily the most reasonable design.

Four Seas combines discarder-double payment with shared payment for small hands and full payment for large hands. Self-draw income is 1.5 times discard-win income; the discarder pays twice as much as a non-discarder, while the large-hand and small-hand distinction still applies. The shared-payment threshold is 25 points.

Example 1: a 15-point hand. On self-draw, the winner receives 15 × 6 = 90, with each other player paying 15 × 2 = 30.

On a discard win, the winner receives 15 × 4 = 60. The discarder pays 15 × 2 = 30, and each other losing player pays 15.

Example 2: a 60-point hand. On self-draw, the winner receives 60 × 6 = 360, with each other player paying 60 × 2 = 120.

On a discard win, the winner receives 60 × 4 = 240. The discarder pays 60 × 4 − 50 = 190, and each other losing player pays 25.

Zung Jung's payment system is also supported as an option. Payment systems deserve a separate discussion.

V. Other details

Four Seas Basic lists recommended supplementary rules, such as a dead wall and not allowing multiple wins on a single discard. I recommend adopting them, as they should improve the balance between offense and defense and add strategic depth to hand-building mahjong.