Suji – How mahjong is played.
What is Suji in Mahjong?
Suji refers to the logical relationships between tiles based on potential two-sided waits (ryanmen waits). Understanding Suji allows players to predict which tiles are more likely to be safe or dangerous to discard.
This concept is based on two-sided waits, so honor tiles are not involved in Suji logic.
Let’s start with a basic example of Suji. Below is the Suji relationship for . The tiles and form a two-sided wait, making them the paired tiles for .
Suji Combinations
There are three basic Suji combinations in Mahjong. It's helpful to memorize these groups first:
- 1・4・7
- 2・5・8
- 3・6・9
There is one important point to note: the central numbers 4, 5, and 6 are connected to Suji on both sides, while the edge numbers only connect to Suji on one side.
For example, the Suji for 1 only connects to 4. Tile 7 is not part of 1’s Suji. This is referred to as a "Single-Sided Suji".
There are also concepts like "Visible Suji" and "Middle Suji", which we will explain next.
Explanation of Key Terms:
- Single-Sided Suji (Kata-Suji): Used to describe edge numbers like 1 and 9, which only connect to one Suji.
- Visible Suji (Omote-Suji): Refers to Suji that are directly apparent based on discarded tiles.
- Middle Suji (Naka-Suji): Refers to Suji patterns in the middle of the number sequence, often with additional strategic implications.
Visible Suji, Inner Suji, and Single-Sided Suji
- Visible Suji: The two Suji located on the outer sides of 4, 5, and 6.
- Inner Suji: The single Suji located inside each pair, such as "1 and 7," "2 and 8," or "3 and 9."
- Single-Sided Suji: The single Suji located on one side of 1, 2, 3, 7, 8, or 9.
These categories classify Suji into three types: **Visible Suji**, **Inner Suji**, and **Single-Sided Suji**.
Regardless of the category, Suji always follows the same definition: "the paired tiles that form two-sided waits." The difference lies only in the way they are viewed or applied.
Understanding these categories is key to effectively using Suji, so be sure to grasp this concept thoroughly.
Visible Suji
Visible Suji refers to the two Suji located on the outer sides of 4, 5, and 6.
For example, has two outer Suji, and , which are called Visible Suji.
While the example uses the Suji group "2・5・8," the same logic applies to "1・4・7" and "3・6・9."
Inner Suji
Inner Suji refers to the single Suji located inside each pair, such as "1 and 7," "2 and 8," or "3 and 9."
For example, the pair and has an inner Suji , which is referred to as an Inner Suji.
While the example uses the Suji group "2・5・8," the same logic applies to "1・4・7" and "3・6・9."
Single-Sided Suji
Single-Sided Suji refers to the single Suji located on one side of 1, 2, 3, 7, 8, or 9.
For example, and each have a single Suji on one side, , which is referred to as a Single-Sided Suji.
While the example uses the Suji group "2・5・8," the same logic applies to "1・4・7" and "3・6・9."
Reading Safe Tiles Using Suji
- Suji Reading: Inferring safe or dangerous tiles based on Suji logic.
- Safe Tile: A tile unlikely to help the opponent win.
- Furiten: A rule where a player cannot win with a tile they have previously discarded.
- Two-Sided Wait: A winning hand waiting on two consecutive tiles.
The practice of using Suji logic to deduce safe or dangerous tiles is called **Suji Reading**.
This section explains how to read safe tiles. The explanation for reading dangerous tiles will come later.
First, let's clarify the meaning of a safe tile: A **safe tile** is one that is unlikely to complete your opponent's winning hand, meaning it is safe to discard.
Let’s start with the conclusion:
You can infer safe tiles by identifying the Suji of tiles already in the discard pile.
For example, if a player is in tenpai (ready to win) and has discarded , you can infer that the Suji tiles and are likely safe to discard.
The reasoning is simple: If one of the waiting tiles in a two-sided wait has already been discarded, the other waiting tile cannot be used to win (this is called furiten).
The Theory Behind Suji Reading
Suji reading is based on two key concepts:
- Two-sided waits
- Furiten
The logic of Suji reading starts with the **assumption that your opponent is using a two-sided wait**.
This assumption is reasonable because many players aim for two-sided waits, as they are more advantageous compared to single-tile waits or inside (kanchan) waits.
However, if your opponent is not using a two-sided wait, Suji reading will not apply.
Keep in mind that Suji reading is a technique to reduce the risk of dealing into a winning hand when you cannot rely on absolute indicators like existing safe tiles.
Now, let’s explore a specific example.
Below are the discarded tiles of a player who is already in tenpai. Let’s analyze these tiles using Suji reading.
Opponent's Discards
Suji reading applies only to number tiles in the context of two-sided waits, so let’s focus on the number tiles among the discards.
First, let’s analyze . Assuming the opponent is using a two-sided wait, the following two-sided wait would involve , which has already been discarded, making it furiten:
Furiten Two-Sided Wait
Because this wait is furiten, we can conclude that this two-sided wait does not exist. Therefore, we can deduce that the Suji of the discarded tile , specifically the other tile in the two-sided wait , is also a safe tile.
This is the basic logic behind reading safe tiles using Suji. The same logic can be applied to other number tiles in the discard pile. However, there’s one issue.
The issue is that the Suji of is a **Single-Sided Suji**.
Single-Sided Suji Are Incomplete
As explained earlier, a Single-Sided Suji refers to the single Suji located on one side of 1, 2, 3, 7, 8, or 9.
As you might notice, the Single-Sided Suji has another Suji on its opposite side. This means the following two-sided wait is still possible:
Non-Furiten Two-Sided Wait
In this example, has not been discarded, so it is not furiten, and cannot be considered a safe tile. This is why Single-Sided Suji are incomplete.
You should only rely on Single-Sided Suji when there are no **Visible Suji** or **Inner Suji** and no other way to deduce safe tiles!
Use “Visible Suji” and “Middle Suji” for Suji Reading
Let’s revisit the number tiles in the previously mentioned discard pile.
Can you identify the tiles with “Visible Suji” and “Middle Suji” among them?
Suji Reading Example with Visible Suji
First, the Suji of is a **Visible Suji**.
In this example, the following two-sided waits involving in the discard pile are furiten:
Furiten Two-Sided Waits
Thus, you can conclude that the tile corresponding to the Visible Suji of , which is , is a safe tile.
Suji Reading Example with Middle Suji
Next, let’s examine and . Individually, these are Single-Sided Suji, but together in the discard pile, they form a **Middle Suji**.
In this example, the following two-sided waits involving and in the discard pile are furiten:
Furiten Two-Sided Waits
Therefore, the tile corresponding to the Middle Suji of and , which is , can be considered a safe tile.
Suji Trick
A **Suji Trick** refers to a strategy where you turn the concept of Suji reading against your opponent, causing them to discard a tile that will lead to their loss.
Although it’s not a direct method of reading safe tiles, this strategy uses the concept of Suji reading to mislead the opponent, which is why it is introduced here.
Take a look at the following discard pile and hand of your opponent.
Opponent's Discard Pile
Opponent's Hand
In this case, the opponent's wait is a **kanchan wait** for .
If the opponent does not have any visible safe tiles, they may rely on Suji reading to estimate the winning tile. Based on the discard pile with and , they may incorrectly deduce that the winning tile is a safe tile and discard it. This is the **Suji Trick**.
Reading Dangerous Tiles Using Suji
Now, let's explain how to read dangerous tiles using Suji.
There are three main ways to read dangerous tiles:
- Ura-Suji
- Aida-Yonken
- Suji Bridging
It may seem a bit complicated at first, but let’s give it a try.
Ura-Suji
Ura-Suji refers to the tile next to a discarded tile and its corresponding Suji.
For example, if is in the discard pile, the adjacent tile and its Suji, , are considered Ura-Suji.
This Ura-Suji can be considered a dangerous tile.
Example of Ura-Suji
The Theory Behind Ura-Suji as Dangerous Tiles
For example, let’s say your hand includes , , and . If or comes, a sequence will be completed, so becomes less necessary. Even if comes in, forming two pairs like + and + , would still be the same waiting tile, making it inefficient. Therefore, is likely to be discarded early in the game.
Of course, it's important to be cautious of edge tiles too. For example, if you have a **kanchan wait** with and , and you draw , you might discard and switch to a two-sided wait with and . In that case, the two-sided wait + means that and will be dangerous tiles as they correspond to the Ura-Suji of .
Especially tiles like , which are near the center of the number range, are more likely to become dangerous tiles for other players later, so they tend to be discarded earlier.
Aida-Yonken
Aida-Yonken refers to the situation where two tiles with the same Ura-Suji are discarded. It's a bit tricky to explain with words, so let's take a look at an example.
Example of Aida-Yonken
As you can see, the Ura-Suji for and are the same tiles. This is Aida-Yonken.
When tiles forming an Aida-Yonken pattern are discarded, it means that the overlapping Ura-Suji are dangerous tiles, making them even more hazardous.
By the way, between the discarded tiles and , there are four tiles: , , , and , which is why it’s called Aida-Yonken.
Of course, Aida-Yonken doesn’t only apply to combinations like "1-6"; "2-7", "3-8", and "4-9" also form Aida-Yonken relationships.
The only exception is "5", which doesn’t have any Aida-Yonken tiles that form such a pattern.
Matagi-Suji
Matagi-Suji refers to the Suji that crosses over a discarded tile. Let's look at an example.
Example of Matagi-Suji
This is a Matagi-Suji in relation to . and , as well as and , are the Suji that cross over .
It may seem a bit complicated, but in simple terms, these are the four tiles on either side of the discarded tile.
However, "2-8" forms a special case, and "1-9" cannot cross over edge tiles, so they don’t form a Matagi-Suji.
Matagi-Suji with 2 and 8
Since Matagi-Suji involves crossing over a discarded tile, does not form a Matagi-Suji across , nor does form a Matagi-Suji across .
The Theory Behind Matagi-Suji as Dangerous Tiles
Matagi-Suji shares a similar concept with Ura-Suji, with just a slight difference in its premise.
In the case of Matagi-Suji, let's assume you have a hand with . This hand is in a two-sided wait with , and can also be used as an Ace or developed into a Pung, which is a very strong shape.
As the hand progresses and other sets are completed, you will eventually have to discard either or . Statistically, it’s likely that you would discard and wait for and to complete the hand. In this case, when is discarded, you can deduce that and are dangerous tiles, corresponding to the Matagi-Suji.
One thing to remember is that the player observing the discard will only know that has been discarded. You must also consider the possibility that was discarded from a shape like . This allows you to deduce that the opponent might be waiting for and as a two-sided wait, with and as other possible options.
Additionally, Matagi-Suji becomes particularly useful when considering discard tiles from the mid-game to the late game. Since the shape is so strong, players are likely to maintain it as their hand develops.
Things to Do Before Reading the Suji
Up to this point, we have explained how to read safe and dangerous tiles using Suji, but Suji reading is a risky method used when you don’t know for sure what the safe tiles are.
Before reading Suji, make sure to learn how to check for safe tiles first.
The most efficient and safest way to discard tiles is in the following order. The meaning of each step is explained below.
- Matching Discards
- Live Tiles
- Complete Safe Tiles
- Suji Reading
Matching Discards
Matching Discards means discarding the same tile that was discarded by the player above you in the same round. "Same round" refers to the period until it comes back to your turn, i.e., after one full cycle of turns.
For example, if the player above you discards a right before your turn, you can safely discard that because it is a confirmed safe tile. This is because once the player above you discards , it becomes "Furiten" (a state where they cannot win with that tile).
Furiten within the same round means that, whether intentional or not, you cannot win with a tile that you missed the opportunity to declare a win with in that round.
The important part is matching the discard of the player above you. If you match their discard, all other players are also in Furiten for that tile, and no one can win with it.
However, if you match a discard from the player across from you, the player above you can resolve their Furiten when it’s their turn, and they can win with that tile. This is called "Yamagoshi" (skipping over the mountain).
Live Tiles (Genbutsu)
A **Live Tile** (Genbutsu) is a tile that matches one discarded by another player. For example, if Player A discards a , that becomes a live tile for Player A, meaning Player A cannot win with that .
This strategy takes advantage of the Furiten rule, where a player cannot win with a tile they have discarded. Unlike Furiten within the same round, this Furiten is permanent, and the live tile remains a safe tile. However, even though a live tile is safe, if another player draws it, they may still win.
The following diagram shows a live tile for the player in the West position (the one at the top in the image). The key point is that not only the West player's discards but also any called tiles (Pon or Chi) and all the discards after declaring Riichi (ready hand) from all players also become live tiles for the West player.
Live tiles also include tiles called by other players. In the diagram above, South has called a **9** from West, so that **9** becomes a live tile for West.
All tiles discarded after declaring Riichi are live tiles. In the diagram, all the tiles discarded by players East, South, and North after West’s Riichi become live tiles for West. This is because if a tile is discarded after a Riichi, it cannot be used to win again due to the Furiten rule.
Complete Safe Tiles
Complete Safe Tiles are tiles that have been discarded by all players. These are tiles that will never be won by any player. These complete safe tiles are always guaranteed to be safe, so if matching discards or live tiles are available, prioritize discarding those instead.
Summary
In Mahjong, avoiding getting caught by another player's winning hand (ron) is crucial to winning. Even if you manage to score big and win with a high score, if you end up discarding a tile that causes you to lose to another player, it's unlikely you’ll end up in first place.
The key principle in any competitive game is “win more, lose less.” Take advantage of the rare opportunities, and if there’s no chance to win, use Suji reading to defend and avoid losses!
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