Strategy guide

Anyone can tap groups. Clearing the board is another matter: most players never do. The rules take a minute to learn (they're all in How to play); this guide is about playing well. Think of it as a chess book: principles first, then how to read a position, the traps, the endgames, a game played through with notes, and puzzles to solve.

Every board below is live, on the real rules. Most have Hint and Show me buttons, worked out by a search of every possible line of play, so a hint is always the best move there is, and every number quoted about a board has been checked the same way.

Part 1

The score, taken apart

Everything in this guide follows from how GAME keeps score, so start there. At every moment, your score is:

Three things follow at once:

• A pair earns nothing in itself. (2 − 2)² = 0. Its only value is the two tiles it takes off the board, and what it does to the tiles around it. That's not a small value: see small moves win games.
• Big groups grow fast. A group of 10 earns 64; of 20, 324. Doubling a group roughly quadruples it.
• Bonuses dwarf both. Each kind cleared doubles the last, 100 up to 1,600, and a clear board collects all five: 3,100.

What things are really worth

Put side by side, the numbers make the case better than any words:

The very last tile you take is worth 1,600 on its own, more than a 35-tile group, and you'll rarely see a group of 35. A game that clears the board beats almost any game that doesn't.

The three priorities

Chess players learn "develop your pieces, control the centre, castle early". GAME's equivalents, in order:

1. Keep the clear alive. Before every move, ask: can this board still be emptied after it? If a move would leave a kind with one tile, or a pattern that can't be broken, it's a bad move, whatever it scores.
2. If the clear is gone, clear whole kinds. Each one pays double the last.
3. Then make big groups, of every kind you take. Not just the last one: the kinds you clear on the way are where most of a game's group points come from (grow the kinds you clear).

The evidence is stark. GAME's app has a planner that searches ahead (it gives the app's hints and plays when you "Watch GAME play"). On fresh 9 × 19 deals, under these rules:

Taking the biggest group every time scores no better than tapping at random, and never clears a board. Playing for the clear scores thirty times as much. The rest of this guide is how to play for the clear yourself.

Part 2

Look before you tap

Strong chess players run a quick check before every move. Here's GAME's, in the order that catches the most mistakes:

1. Count the kind. How many of this kind are on the board? If this group is all of them but one, stop: you're about to strand the last one (the all-but-one trap).
2. What falls? Look up every column the group is in. Every tile above it drops. Where does each land, and what will it touch?
3. Does a column empty? If so, everything to its right slides left. Look along the whole row for new neighbours.
4. Is there a bigger version of this group if I wait? Is a same-kind tile one move away from joining it?
5. Could I take something else first? A pair elsewhere that does no harm might make this group bigger, or line up two more.

It sounds slow, but after a few games it becomes a glance. Every section in this part is one of those questions, practised.

The group map

The first skill is simply seeing the board as groups rather than tiles: where the groups are, how big they are, and which tiles are alone. The map below does it for you. Try playing with it on, then turn it off and see how much of it you can still see.

Notice how often a move changes groups it didn't touch: a pair taken low down can merge two groups above it, or split one. Reading the board means reading those knock-on effects.

Dead tiles

A tile is dead when it can certainly never be taken. There's one sure sign: it's the only tile of its kind left. A group needs two, so a kind down to one tile can never be cleared. And if any tile is dead, the board can't be cleared: the clear is gone, and it's time for the plan in when the clear is gone.

Lone tiles aren't dead. A lone tile has no partner beside it, but it may have partners elsewhere that falling and sliding can bring to it. Watch the counters on the plank: a counter at 1 is a dead tile.

Quiet moves and loud moves

Moves differ in how much they disturb the board, and it pays to know which kind you're making:

• A quiet move takes a group that has nothing above it and doesn't empty a column. Nothing else moves. Quiet moves are safe: whatever you were planning elsewhere still stands.
• A loud move takes tiles low down, so everything above falls, or empties a column, so everything to the right slides. Loud moves rewrite the board: great when you've pictured the result, dangerous when you haven't.

Joining by gravity

The commonest way to build a group: take whatever separates two same-kind groups in a column, and let the upper one fall onto the lower one.

How to play has this board live (boards A and B): the same eight chicks scoring 16 or 44 depending only on the order of two moves. Look for separators: short runs of another kind wedged between two groups of one kind. A separator that is itself a pair costs nothing to take, and turns two groups into one.

Gravity works sideways too, in a sense: when tiles fall in one column, they land beside new neighbours in the columns either side. A frog that drops two squares may land level with a frog in the next column. So when you look up a column, look at both sides of every landing square.

Joining by sliding

Columns only close up leftwards, and only when a column is completely empty. So to bring two columns together, empty everything between them. It usually takes several small moves, and it's often worth it.

Lowering a stray

A stray is a tile whose partners are elsewhere. You can't move it directly, but you can take tiles under it so that it falls, and tiles to its left (a whole column of them) so that it slides. Work out where its partner is, then which tiles must go to bring the two together.

The same idea works in reverse: sometimes you lower the partner to the stray. And sometimes the stray is best left alone, because the end of the game will bring it home (see the last kind always comes together).

Part 3

The all-but-one trap

This is the single most common way a clear is lost, and it's easy to walk into because it looks like a good move. A big group of one kind sits there, worth a lot. You take it. But one tile of that kind wasn't in the group, and now it's the only one left of its kind. It's dead, and so is the clear.

The trap has a slower cousin: taking a group that leaves exactly two of its kind far apart, with no way left to bring them together. They aren't dead yet, but they may as well be. Before a big take, look at the leftovers of its kind and ask how they'll ever meet.

The cost of grabbing early

Why is taking the largest group every time so bad? Because big groups hold the board together. A big group of chicks is the thing that lets the other kinds around it be cleared in small pieces. Take it early and the tiles around it collapse into a jumble, strays everywhere, several kinds with a tile or two stranded.

The app's planner measured it. From a fresh 9 × 19 deal, its hints clear about 91 boards in 100. Play just 10 "take the largest group" moves first, and it can only clear 49 of them. After 20 such moves, only 9. The damage is done in the opening, long before the board looks difficult.

Part 4

The last kind always comes together

Here's the most useful fact in the game. When only one kind is left on the board, however scattered it was, it is always one single group, and one tap takes the lot.

Why: tiles always fall, so every column stands on the bottom row. Empty columns always close up, so the bottom row has no gaps. With one kind left, the whole bottom row is that kind, and every tile is joined to it through its own column. (Unless there's only one tile, of course.)

Two big consequences:

• You never have to join the last kind yourself. Two tiles of it at opposite corners are fine, as long as everything else can be cleared around them. The end of the game does the joining for you.
• The last tap is worth 1,600, however small it is. The bonus is the same for a pair as for a group of thirty. So the last kind doesn't have to be hoarded for one enormous final group: in the app planner's own cleared games the last tap is usually a pair or a three, and the big groups came earlier.

So the real endgame isn't one kind, it's two: getting from two kinds to one.

Two-kind endgames

With two kinds left, the board can be anything from trivial to impossible. The shapes to recognise:

Stripes (a column of one kind, then a column of the other) always clear: take a column, and its neighbours slide together. Checkers never do. Real endgames sit between the two, and the skill is steering towards stripes: take the tiles that break up the checkerboard pattern before it forms, and prefer moves that leave whole columns of one kind.

Two-kind positions are small enough to calculate. Before each move, picture the board after it; if you can, picture the board after the next move too. Undo is cheap practice (using undo well).

Counting in the endgame

From about 30 tiles left, start counting every kind, every move. The plank's counters do it for you. What you're looking for:

• A counter at 1: the clear is gone. Switch plans (when the clear is gone).
• A counter at 2: two tiles that must meet. Where are they, and what has to go for them to touch? If that kind is the one you're keeping for last, they'll meet by themselves; otherwise, you must bring them together.
• A counter at 3: all three must go together, as one group of three. Take two of them as a pair and the third is dead. (Unless it's your kept kind: then they'll come together by themselves.)
• In general, a kind is cleared in pieces of two or more, so plan its pieces: four tiles go as two pairs or one four, five as a pair and a three or one five. Any plan that leaves a piece of one has lost the clear.

Part 5

Keep one kind

This is the core strategy for clearing the board, the one the app's planner uses and the one its hints teach:

1. Pick one kind to keep. It will be the last to go, so it's the one kind you never have to join.
2. Clear the other four around it, pairs included where that's what it takes, and never leave one of them with a stranded tile. Where you safely can, grow them before you take them.
3. Take what's left of the kept kind last, when it has come together by itself.

Keeping a kind doesn't mean never touching it. When a big group of it is ready, taking it is fine, as long as enough of the kind stays behind to come together at the end: two tiles are enough, since the last kind always joins up. The app's planner does exactly this. In its cleared games the kind that goes last is taken in about ten pieces, not one.

Why it works: the kept kind is the one you never have to worry about joining (the last kind always comes together). By ignoring it, you turn a five-kind problem into a four-kind one. And the kept kind acts as a scaffold: while it stays on the board, it props up the columns, so the other kinds fall and slide in predictable ways around it.

On that board, only the chicks can be the last kind in a clear, and only two of the four opening moves keep the clear alive. The six chicks were the big, obvious group, and seven chicks were on the board: the all-but-one trap again.

Which kind to keep

This is the hardest decision in the game, and there's no simple rule. The app's designers tested the obvious ones against its planner on 100 deals: keep the most numerous kind, the one in fewest clumps, the one with fewest strays, the one lowest on the board, the one spread across the most columns. None picked the best kind more than 28 times in 100, where picking at random would manage 20. What does help:

• A kind you can't join is a good candidate. If two tiles of a kind are far apart with no way of meeting, keeping that kind means you never have to join them (the annotated game below turns on exactly this).
• A kind in a big group you'd otherwise be tempted by. Keeping it removes the temptation, and the group only grows.
• Try, and undo. Play a few moves with one kind in mind. If another kind starts to strand, step back and try keeping that one. It costs 10 points a step; losing the clear costs 1,600.
• Commit. Switching the kept kind halfway through is how a board ends with two kinds each a tile short.

Grow the kinds you clear

A clear always earns the same bonuses, 3,100 on a full board, and every tile comes off, so every clear scores the same apart from one thing: the size of its groups. A kind of thirty tiles taken as fifteen pairs adds nothing to the (n − 2)² column. Taken as three groups of ten it adds 192. So before you take a group of a kind you're clearing, ask: could it join another group of its kind first? The tools are the ones from Part 2: take the separator between them and let gravity do it (joining by gravity), or empty the columns between them (joining by sliding).

The app's planner measured what it's worth. On 200 fresh 9 × 19 deals it played twice: once counting group points, and once playing for the clear alone, with no reason to grow anything. On the deals both cleared, growing the kinds it cleared on the way scored about 230 more, and the (n − 2)² of those groups more than doubled.

But look at the other half of the result. Chasing groups, the same search lost the clear on 26 boards in 100; playing for the clear alone, on 9. Each lost clear costs at least 1,600, worth seven boards' growing. So growing is a second priority, and a strict one:

• Grow only what's safe to grow. Joining two groups of a kind usually means taking something else first. If that something is the last-but-one of its kind, or leaves two tiles with no way to meet, don't.
• Mind the all-but-one trap on the way. A grown group that is all of its kind but one is worse than two small ones (the all-but-one trap).
• When in doubt, take the pair. A clear with small groups beats a big group without a clear, every time.

The app plays it the same way. Its hints now play for the clear alone, which cleared 91 boards in 100 where counting group points cleared 74. When you "Watch GAME play", it searches far enough ahead to see which groups can be grown safely, and grows them.

Small moves win games

Players are drawn to big groups, and the dog sulks at pairs. But in the games where the app's planner clears the board, more than half of all moves are pairs. Pairs are how you make room, remove separators, lower strays and clear a kind in the pieces it comes in. A pair taken in the right place is often the best move on the board.

What pairs aren't good for is points. So use them for position, and take your points from groups you've grown, of any kind (grow the kinds you clear).

An annotated game

Everything so far, in one short game. Press Next move to play each move, with a note on why.

Opening, middle game, endgame

On a full 9 × 19 board, a game has phases, as in chess.

The opening (the first 20 or so moves)

• Don't grab. The damage from early greed is done here.
• Work out which kinds are big and scattered, and form a first idea of which to keep.
• Take small groups high on the board and on the right, where they disturb least, and pairs that join bigger groups.
• Leave the biggest groups alone. They're your scaffolding.

The middle game

• Commit to a kept kind.
• Clear one other kind at a time where you can: a cleared kind is a bonus banked and one less thing to strand.
• Watch the counters. Any kind getting low needs its last tiles brought together while there's still room to move.
• Use loud moves on purpose: to bring columns together, to drop strays onto partners.

The endgame (the last 30 tiles or so)

• Count every move (counting in the endgame).
• Get to two kinds, then steer for stripes (two-kind endgames).
• Calculate, and use undo to check lines. The board is small enough now to see to the end.
• Last tap: the kept kind, all at once.

Part 6

When the clear is gone

Sometimes the clear goes: a kind is down to one tile, or two tiles have no way left to meet. Don't give up; change plans. The new plan is:

1. Clear as many whole kinds as you still can. Each is worth double the last: four kinds cleared is 1,500, three is 700. From positions that couldn't be cleared, the planner found clearing kinds gained 700 to 830 points, where building one big group gained 170 to 360 (measured under the older 2014 scoring; the 1995 doubling only strengthens it).
2. Keep what can't be cleared together, in as few groups as possible, so it can at least go in big pieces.
3. Give up on the dead kind entirely. Its tiles cost a point each, which is nothing: use them as scaffolding.

On that board, taking the largest group every time scores just 26. The best line, clearing the chicks and the kennels around the frog, scores 368.

Using undo well

Undo costs 10 points and it's unlimited. Compared with 1,600 for the last kind, it's nearly free, so use it:

• To explore. Not sure what a loud move will do? Make it, look, and undo if you don't like it. That's 20 points (there and back) for perfect information.
• To test a kept kind. Play five moves keeping chicks; if something strands, undo and try oranges.
• To study the endgame. At game over, "Undo the last move" is on the panel. Step back five moves and look for where the clear was lost. That's how you get better.

The app's high-score tables record how many undos each score used, so a score played straight is always distinguishable from one worked out with undo. Both are honest; it's your choice which you're chasing.

Part 7

Puzzles

Like chess problems, graded by stars. Each board can be cleared (or, for the last two, has a best score to find), and the search has checked how many openings work. Hint rings the best next move from wherever you are; Show me plays the solution. Undo is free here. The board tells you the moment a move makes the clear impossible.

Warming up

Reading ahead

Four kinds

Hard

No clear: find the best score

Part 8

Common mistakes

1. Taking the biggest group because it's big. It scores no better than random play. Ask what it holds together.
2. The all-but-one trap. Check the counter before every big take.
3. Forgetting what falls. Look up every column a group is in before you tap.
4. Ignoring the right-hand side. Emptying a column moves everything to its right. The best join on the board is often three columns away.
5. Switching the kept kind. Commit, or you end with two kinds a tile short each.
6. Leaving a kind at two tiles, far apart. Bring pairs together while there's still room to move them.
7. Giving up when the clear goes. Four kinds cleared is still 1,500.
8. Being afraid of undo. Ten points to see the future is a bargain.

Glossary

Group

Two or more touching tiles of one kind (touching means sharing a side). Taken all at once.

Lone tile

A tile with no neighbour of its kind. It can't be taken now, but may join a group later.

Dead tile

The only tile of its kind left. It can never go, so the board can't be cleared.

Clear

Emptying the board, which earns all five bonuses: 3,100.

Kept kind

The kind you leave alone to take last, in one group, when everything else has gone.

Separator

Tiles of another kind between two groups of one kind. Take it, and the groups join.

Stray

A tile whose partners are elsewhere on the board.

Lowering

Taking tiles under a stray so that it falls beside a partner.

Quiet move

A move that makes no other tile fall or slide.

Loud move

A move that makes tiles fall, slide, or both.

Stripes and checkers

The two extremes of a two-kind endgame: whole columns of each kind (always clears), and alternating tiles (never has a move).

The all-but-one trap

Taking a group that holds every tile of its kind but one, leaving that one dead.

Greedy play

Always taking the largest group. It scores about the same as random play.