Nesting Three Strategy: Covering, Uncovering and Long Streaks

Updated October 2026

Nesting Three looks like a three-by-three line game, but it plays more like a small chess problem. Pieces can sit on top of each other, a piece that seems settled can be lifted again, and a single careless lift can hand the round to the computer. This guide goes through the rules exactly as the game applies them, the order in which wins are checked, how the computer gets stronger as your streak grows, and the habits that keep a streak alive.

What a move can and cannot be

Both sides start with six pieces: two small, two medium and two large. Your dark pieces wait in the tray under the board and the light ones in the tray above it. On your turn you make exactly one of two kinds of move. You can bring a new piece in from your tray, or you can pick up one of your own pieces that is currently visible on top of a stack and put it somewhere else.

Wherever the piece goes, the destination has to be either an empty cell or a cell whose top piece is strictly smaller. Colour does not matter, so you are allowed to cover your own small piece with your own medium. Equal sizes never stack, and a piece you lift cannot be dropped back on the cell it just left. Only the top piece of each cell is visible and counts towards a line. Anything below it is out of play until the cover is lifted.

One consequence is worth learning early: nothing in the game is bigger than a large piece, so a large piece can never be covered. Once a large is on the board, that cell belongs to its owner until the owner moves it. Mediums can only be covered by a large, and smalls by a medium or a large. Look at the trays before every move. If the computer has already used both larges, your mediums cannot be covered by anything it can still bring in, and the only large pieces that could cover them are the two already on the board.

How the game decides who won

After every move the game looks for complete lines, and it always checks the opponent of the player who just moved first. If that opponent has three visible pieces in a row, the opponent wins, even if the move also completed a line for the mover. Only when the opponent has no line does the game check whether the mover has one.

This matters because of uncovering. When you lift a piece, whatever was beneath it becomes visible again. If that reveals a computer line, you lose, and making your own line in the same move does not save you. But the check happens after your piece has landed, not at the moment you lift it. So if lifting a piece would reveal a computer line, you can still escape by dropping that same piece onto one of the other two cells of the line, provided the piece you are carrying is bigger than the top piece there. The line is broken before anyone looks at it.

The same order works in your favour. If the computer lifts one of its pieces and uncovers a line of yours, the round is yours. At the higher levels it will not do that on purpose, but at the lowest level it makes a lot of random moves, and the only thing it checks before a random move is that the move does not reveal your line. It does not check whether you can win on your next turn.

The value of each size

Think of the large pieces as the anchors of the game. They cannot be covered, they can cover anything, and once you have placed one you can still move it later to cover a threat somewhere else. The computer weighs its larges in its evaluation, counting each large it still has in reserve as worth more than a medium, so at the stronger levels it will not throw them away early either.

Small pieces are the opposite: anything can cover them, so they are mostly useful as filler, as bait, or as a piece you deliberately cover with your own bigger piece to keep it safe underneath. A small piece of yours hidden under your own large is a stored point on that cell. If you later move the large away, your small reappears, and that can be the third piece of a line.

Mediums sit in between. Against an opponent with no larges left in reserve, a medium in an empty cell is almost as solid as a large, which is why counting the pieces left in each tray matters so much.

Opening ideas

The centre cell is on four of the eight lines, and the computer's evaluation gives a bonus for holding it, so expect a fight over it. If you take the centre with a small piece, any medium or large can take it straight back. A large in the centre is permanent until you move it, which makes it the most common strong opening. Corners come next, as each sits on three lines.

Who moves first alternates. Your first round of a new game starts with you, the second with the computer, and so on. When the computer opens, your first decision is whether to cover its piece straight away, which only works if you use something bigger, or to build elsewhere and keep your larges in hand.

A useful rule of thumb: never spend your second large unless it wins the round or stops a line. With one large in your tray you always have a reply to a two-in-a-row, because a large can be dropped on any cell that is not already topped by a large.

How the computer gets stronger

The computer's level depends only on your current streak. At a streak of zero or one it searches two moves ahead, but 70 percent of the time it ignores the search and plays a random move. At streaks two to four it searches four moves ahead and plays randomly 35 percent of the time. At five to nine it still searches four moves ahead, with random moves only 12 percent of the time. From a streak of ten onwards it never plays randomly and tries to search five moves ahead, with a thinking limit of 0.7 seconds per move: it first settles on its four-move answer, and if the deeper search has not finished in time it plays that answer instead. At every level it always takes an immediate win if one exists, so leaving it a single open line is never safe.

The practical meaning is that early rounds reward ambition, because the computer often fails to block. Set up two threats and it will regularly miss one. In the middle levels it blocks far more reliably and starts to punish loose pieces. From ten onwards each round is a real game, and the safest approach is to play solid, keep a large in reserve and wait for it to overextend.

Draws, the move limit and pressing New

A round that reaches 60 moves in total, counting both sides, is declared a draw, and a draw ends your streak just like a loss: the game-over card appears with the streak you had built. A round also ends as a draw if the computer has no legal move. With six pieces each and constant lifting, long rounds do happen at the top level, so a draw is not a safe place to shelter. Keep pressing for a line of your own before the move count runs out.

Be careful with the New button. If your streak is above zero, pressing New ends the game at once and shows the game-over card with your current streak, the same as a loss. Your best streak is stored on this device, and any streak above zero can be sent to the Hall of Fame from that card.

Habits that protect a streak

• Remember what is underneath. A cell that hides pieces shows a small dot in its corner, but the dot does not tell you whose piece is below or how big it is. Keep track yourself, especially of computer pieces you have covered on a line.
• Before every lift, ask what appears. If the cell you are leaving hides a computer piece that sits on a line with two other computer pieces, either do not lift, or make sure the piece lands on that same line.
• Count the trays. The number of larges each side has left decides which of your pieces are safe. Recount after every computer move.
• Prefer double threats. Two open lines at once beat any single block, even at the highest level, and a well-placed large often creates both.
• Watch the last move highlight. The cells involved in the most recent move are outlined. When the computer moves a piece, both its old and new cells are marked, which tells you what it just uncovered.

Long streaks come from patience rather than tricks. Treat every lift as a question about what lies below, keep a large in reserve, and the computer will run out of ideas before you do.