Sotogawa: Taking to the extremes

You know your suji and your kabe. What next? Sotogawa is something that is occasionally discussed in Western theory circles but I’ve seen it misunderstood, too.

Sotogawa literally means the outer side. Imagine the centre of the suit being at five, you move further out to the terminals. If you have a 4, the outer tiles are the 123. if it’s a 3, the outer tiles are 12.

So far, so obvious. How can this be used to your advantage if you need to identify a safe(er) tile to avoid dealing in?

Defence

As with most defence (when you’re not playing completely safe), it’s about identifying whether there is something notable in your opponent’s discard pool that will give you insight into how they may have constructed their hand. Your outer edge tiles can only be considered notable if you’re reading on a tile that was discarded in the first row and your opponent’s hand has developed at an average pace (ie. they’ve not declared riichi three or four discards in).

The theory is that a tile discarded early on is either unconnected or a player has been able to complete a group. For example, the following two shapes will generally be held longer.

So if the 3 was thrown early on in their hand’s progress, you can imagine that the player has locked the shape in. Therefore, 12m may be relatively safer.

However, if the 3 is thrown later, then you’re looking at the tiles surrounding it, including 12, being more dangerous. A later throw, you’d be considering a matagi suji read.

Warning!

Earlier discards can be a little more reliable so there will be occasions where a sotogawa read can identify a relatively safer tile. But beware of these caveats:

1) Dora: the positioning of the dora in relation to the discard can make this read dangerous. (Remember, the dora makes behaviour around it less regular!)

2) Yaku: the player may be going for a particular yaku like sanshoku.

3) Riichi: If the player declares riichi very shortly after, this is not a reliable read and, as above, you want to consider if matagi suji is better to apply here.

Sotogawa Summary

Sotogawa the theory that tiles to the outer side of a discard are relatively safer than other tiles.

Sotogawa is based on similar shapes to matagi. However, where matagi is a later read, this is an early read. I’d typically advise you take the read on as early a discard as possible.

In the example below, I would read the 7m to mean the 8m or 9m were relatively safer if I was all out of safe tiles or really determined to push!