Tile Efficiency

Tile efficiency means keeping the partial sets that the most different tiles can finish, and throwing the tile that helps least. Two-sided shapes beat kalong and edge waits because more tiles complete them.

Most turns come down to one question: which tile is doing the least for you? Tile efficiency is the habit of answering it by counting, not by feel.

Count The Tiles That Help

Every partial set in your hand is waiting for something. The more different tiles that can finish it, the sooner it’s likely to finish. That’s the whole idea, and it’s worth making it concrete.

Three partial runs: two-sided, kalong and edge.

Two-sided (4-5): finishes with a 3 or a 6. Two kinds of tile, up to eight copies.
Kalong (4-6): needs the 5 in the middle. One kind, up to four copies.
Edge (1-2): needs the 3, because nothing comes before 1. One kind, up to four copies.
A pair: becomes a Pong with either of the two remaining copies, and you can claim it from anyone.

So a two-sided shape is roughly twice as useful as a kalong or an edge. When you have to break one partial set, break the one with the fewest ways to finish.

Some Shapes Grow, Some Don’t

Two shapes can have the same count today and very different futures. A kalong of 6-8 Dots needs a 7, but a 5 lets you keep 5-6 instead (two-sided), and a 4 makes 4-6-8, which takes a 5 or a 7. An edge of 1-2 Bamboo can only change with a 4, into 2-4, which is still a one-tile wait.

That’s why middle tiles (3s to 7s) are worth more than 1s, 2s, 8s and 9s while you’re building. They join more runs. A lone 5 can become part of 3-4-5, 4-5-6 or 5-6-7; a lone 9 only ever joins 7-8-9.

Spaced by two: a 4 or a 6 makes a run either way.

Shapes like 3-5-7 are sneakily good. Either a 4 or a 6 completes a run, so it behaves like a two-sided shape, with a spare tile left over.

A Worked Choice

Two sets, an Eye of North, and three partial runs. One has to go.

You hold 2-3-4 and 6-7-8 Characters, an Eye of North, and three partials: 3-4 Dots (two-sided), 5-7 Bamboo (kalong) and 8-9 Dots (edge). Fourteen tiles, so one must go.

The two-sided 3-4 stays. The other two each wait on a single kind of tile, four copies at most. But the 5-7 can grow: a 4 makes 4-5, an 8 makes 7-8, both two-sided. The 8-9 can only finish with a 7. Throw the 9 Dots. The 8 left behind can still become 7-8 or 6-8 if a tile arrives, and goes next if nothing does.

Efficiency Isn’t Everything

Counting shapes tells you the fastest route to four sets and an Eye. It doesn’t tell you whether that hand can win. A Singapore win needs at least 1 tai, so a valued pair (a dragon, your Own Wind or the Round Wind) can be worth keeping over a neater run, because it might be your only tai. How To Count Tai shows where they come from.

Safety matters too. A tile that helps you a little but could feed a player showing three sets is often worth throwing away. Safer Discards covers that side.

And look at the table: a two-sided wait whose tiles are mostly face up already is worse than a kalong whose tile nobody has seen. Counting Tiles shows how.