Matagi suji: Difference between revisions

Revision as of 12:21, 16 August 2024

Matagi suji, or "straddle suji", is a form of discard reading. It states that, when a number tile is discarded early, nearby tiles become safer. But, when a number tile is discarded late (especially if the riichi declaration tile), nearby tiles become more dangerous.

When a tile numbered 3-7 is discarded, the tiles within +/- 2 of that tile are affected by matagi suji.
When a tile numbered 2 or 8 is discarded, the 1-4 or 6-9 tiles are affected by matagi suji.

Table

Discard	Remaining in Hand	Matagi suji
2	23	1-4
3	23 or 34	1-4, 2-5
4	34 or 45	2-5, 3-6
5	45 or 56	3-6, 4-7
6	56 or 67	4-7, 5-8
7	67 or 78	5-8, 6-9
8	78	6-9

Theory

Matagi suji relies on the power of a shape like "233" or "334". When a player has a "233", it is unlikely for them to discard a 3 early - turning "233" -> "23" - since it'd come at a loss of tile efficiency. So if a 3 is discarded early, it is less likely for them to have "23" (which waits on 1-4) or "34" (which waits on 2-5) remaining. As the 1-4 wait and 2-5 wait are less likely, an early discarded 3 makes 1-4 and 2-5 safer. Note: tiles towards the outside of a discarded tile are much safer; tiles towards the inside are not much safer than a regular tile.

Conversely, it is more likely for a player to keep shapes like "233" until tenpai. So if a 3 is discarded early, it is more likely for them to have a "23" or "34" remaining. This means an early discarded 3 makes 1-4 and 2-5 more dangerous.

Note: if the riichi declaration tile was a tsumogiri tile (discarded right after drawing it), then number tiles around the last tedashi (discarded from hand) tile are dangerous instead.

Effectiveness

"Tiles nearby the riichi declaration tile" are more dangerous. But, when folding, there usually isn't a need to consider matagi suji. A 4 discarded as a riichi declaration does make the 5 more dangerous, but a non-suji 5 is already very dangerous. It can make an impact when deciding whether to push or fold to begin with, though.

"Tiles outside of early discards" are relatively safe; about as safe as regular suji (but a bit less safe).

External links

Matagi suji danger analysis on Path of Houou
Matagi suji on Mahjong Gem

@@ Line 27: / Line 27: @@
 Conversely, it is more likely for a player to keep shapes like "233" until [[tenpai]]. So if a 3 is discarded early, it is more likely for them to have a "23" or "34" remaining. This means an early discarded 3 makes 1-4 and 2-5 more dangerous.
+Note: if the riichi declaration tile was a tsumogiri tile (discarded right after drawing it), then number tiles around the last tedashi (discarded from hand) tile are dangerous instead.
 ===Effectiveness===
-"Tiles nearby the riichi declaration tile" are more dangerous. When [[fold]]ing, there usually isn't a need to consider matagi suji. A 4 discarded as a riichi declaration does make the 5 more dangerous, but a non-suji 5 is already very dangerous. However, it can make an impact when deciding whether to push or fold to begin with.
+"Tiles nearby the riichi declaration tile" are more dangerous. But, when [[fold]]ing, there usually isn't a need to consider matagi suji. A 4 discarded as a riichi declaration does make the 5 more dangerous, but a non-suji 5 is already very dangerous. It can make an impact when deciding whether to push or fold to begin with, though.
 "Tiles outside of early discards" are relatively safe; about as safe as regular [[suji]] (but a bit less safe).