Bomb, rainbow and ice blocks
A bomb is a space tool, not a scoring tool. A rainbow block is worth nothing until the last cell of a line. And ice punishes you for changing your mind halfway.
Special pieces in a block puzzle look like bonuses. They are not, quite. Each one is a tool with a narrow job, and each one has a characteristic way of being wasted that most players repeat for weeks without noticing. This page is about the jobs and the waste.
Three things show up in Blockwood besides ordinary wood blocks: a bomb, a rainbow single, and ice. They appear at low fixed rates, and those rates never change in response to how well you are doing — there is no mechanism that hands you a bomb because you are in trouble. Treat them as weather, not as rescue.
The bomb
The bomb clears the 3×3 area centred on the cell it lands in. That is nine cells when the whole square is on the board, and fewer when it is not, because the blast is clipped at the edges rather than wrapping or shifting inward.
Do the arithmetic once and you will never place one carelessly again. Land a bomb in a corner and only four of the nine cells exist — the other five are outside the board and simply do not happen. Land it against an edge but not in a corner and you get six. Land it anywhere in the middle four-by-four region and you get all nine. So a corner bomb delivers under half of what the same piece delivers two cells inward.
The second half of the rule is that a blast does not care whether the cells it takes are full. Detonating over mostly-empty space clears mostly nothing. So the ideal landing is easy to state: the densest 3×3 block you can find that sits entirely on the board — the patch of alternating filled and empty cells no ordinary piece has been able to touch for ten moves — and better still if it leaves a row or column one piece from complete afterwards.
Bombs are a space tool, not a scoring tool
Cells removed by a blast pay a small flat amount each — two points per cell. Nine cells at two points is not a score. It is a rounding error next to what a double line clear pays, because the line score grows with the square of the number of lines and then gets multiplied by a live combo.
So never spend a bomb hoping for points. Spend it to get space back, and take the points from the line clears that the space makes possible. A bomb that opens a route to a double clear on your next placement has paid for itself many times over; a bomb that scores eighteen points and leaves the board the same shape has paid for nothing.
The other thing a bomb does, and this is often the best reason to hold one, is remove ice in a single hit.
The rainbow block
The rainbow piece is always a single cell. That is the whole shape — one square, not a bar, not a variable form. It has no special clearing behaviour when it lands, and it does not make the cell it occupies wild afterwards. It settles as an ordinary occupied cell.
People are disappointed by this until they understand where its value sits. Line clearing in this game ignores colour completely: a row clears when all nine of its cells are occupied, regardless of which colours filled them. So a piece whose only property was matching anything would be worth nothing at all. What the rainbow gives you instead is the one property that does matter — a 1×1 fits into any single empty cell, and nothing else in the game does. It is the only piece that can consume an isolated cell with occupied neighbours on all four sides, and the only piece that can finish a line whose last gap is one cell wide between two filled cells.
Which tells you when to spend it. Look across your rows and columns for one that is a single cell short. If there is one, the rainbow finishes it, and if that clear is also the second clear on an iced cell, or the piece that starts a combo you can keep alive across the rest of the hand, better still.
The mistake is spending it as filler. It arrives, it fits everywhere, you drop it into open space to get on with the hand. Now you have used the only key you own on a door that was not locked. Hold it while you place the other two pieces, and let those two decide where the rainbow goes.
One caveat: the hand only refills when all three slots are empty, so holding the rainbow means playing a hand of two. That is usually right, but if no single-cell gap is worth taking and your other pieces are large, place it rather than stalling for a use that may not arrive.
Ice
An ice cell is a cell that has to be cleared twice. The first clear that runs through it cracks it and leaves it in place. The second clear removes it properly. Until then it counts as occupied for the purpose of deciding whether a row or a column is full, which means a line containing cracked ice can still clear normally — the ice just does not go anywhere the first time.
The characteristic mistake is not misunderstanding the rule. It is quitting halfway. You clear a row, the ice cracks, the board shifts around and you go and play elsewhere. Weeks later that same cracked cell is still sitting in the best part of your board, and every plan you make has to route around it.
A cracked ice cell is worse than an ordinary filled cell, because an ordinary filled cell will come out with the next clear through it and the ice will not. So the rule is: decide before the first clear whether you are going to finish. If the ice sits in a region you actually want, commit to clearing that line twice and aim your next clear at it while the surrounding cells are still convenient. If it sits somewhere you were writing off — a far edge, a corner you had already conceded — you can crack it as a side effect and forget about it without cost.
Two things remove ice in one go rather than two: a bomb blast, and the full-board wipe you can spend at full energy. If a level asks you to clear every ice block, that is what those exist for, and it is normally worth steering a bomb toward the cluster of ice rather than toward the densest area.
Putting them together
- Bomb: aim for the densest 3×3 fully on the board. Every cell of the blast that falls outside the edge is thrown away.
- Bomb: judge it by the space it returns and the clears that space unlocks, never by its own two-points-a-cell score.
- Rainbow: it is a 1×1 and its only power is fitting anywhere. Save it for a line that is exactly one cell short, or for an isolated cell that nothing else can reach.
- Rainbow: do not stall a whole hand waiting for the perfect gap — the hand does not refill until all three are gone.
- Ice: two clears, and the first one alone makes the board worse. Commit or leave it.
- Ice: bombs and the board wipe take it in one, so let those handle the ice that sits in space you need.
None of these pieces will save a board you have already fragmented. They arrive at fixed low rates and they do not know how badly your run is going. What they will do is give a well-kept board a way out of the one problem ordinary pieces cannot solve — and that is worth planning for rather than hoping for.
Frequently asked questions
Where should I place a bomb?
In the densest area you can find that sits fully on the board, ideally in the middle four-by-four region. The blast is the 3×3 centred on the landing cell and it is clipped at the board edges, so a corner landing throws away five of the nine cells.
Is the rainbow block a wildcard colour?
Effectively not, because line clearing ignores colour entirely — a row clears when it is full no matter which woods filled it. The rainbow is a single 1×1 cell, and its real value is that a single cell fits into any empty space, including one nothing else can reach.
How many times do I have to clear ice?
Twice. The first clear through it cracks it and leaves it occupying the cell; the second removes it. A bomb blast or the full-board wipe removes it in one hit instead.
Are bombs worth a lot of points?
No. Cells destroyed by a blast pay a small flat two points each, which is trivial next to a multi-line clear, since the line score grows with the square of the number of lines and is then multiplied by your combo. Use bombs to recover space and take the points from the clears that follow.
Try it on a real board
Blockwood is a wood block puzzle on a nine-wide, twelve-tall board, with nothing falling and no dealt dead ends — every hand is checked against the board you actually have before it reaches you. Endless mode, timed mode, hand-built levels and a daily challenge. Free, offline, no ads and no account.