Hidden Fleet

What is Hidden Fleet?

Hidden Fleet is a logic puzzle of ships hidden at sea, known elsewhere as Battleships or Bimaru. A fleet of straight ships lies on a square grid, each one across or down, and no two ships touch, not even at a corner. The numbers along the top and the left of the board say how many ship segments each column and each row holds, and a few cells are shown from the start: water, or a segment that shows its shape, a boat of one cell, the end of a ship or its middle.

Every board has exactly one answer, and it can always be reached by reasoning, never by guessing. Boards come in three sizes: 6 by 6 with a fleet of six ships, then 8 by 8 and 10 by 10 with the classic fleet of ten, from a battleship four cells long to four boats of one cell. A new sea, the same for everyone, arrives every day.

How to play

Tap a cell to say what it holds.

• Marking. A tap marks a cell as water, a second tap turns it into a ship segment, and a third clears it. Hold a cell, or right-click it, to mark water straight away.
• Water in bulk. Drag across cells to mark water on all of them at once (a drag never touches a segment), and once a row or column holds all its segments, tap its number to mark the rest of it as water.
• Shapes. Segments take their shape from their neighbours: a bow, a stern, a middle, or a whole boat of one cell. Cells shown from the start sit on a plate and never change.
• The fleet. The ships above the sea are the fleet to find. Close a ship off with water at both ends and it is crossed off.
• Warnings. A number dims when its line holds exactly that many segments, and turns red when the line holds more, or can no longer reach it. Segments that touch another ship turn red too.
• Score. Your score is the time to place the whole fleet, plus 30 seconds for every hint. Every board size has its own leaderboard.

Strategy tips

1. Start with the zeros. A 0 makes its whole line water. A number as big as the open cells left in its line makes every one of them a segment.
2. Water around every segment. Ships never touch, so the four corner cells of every segment are water, and so are the cells beyond both ends of a finished ship.
3. Read the shapes shown. An end shows which way its ship runs, a boat of one cell has water all round, and a middle runs on both ways along the side that is not shut.
4. Place the big ships first. The battleship needs four cells in a row, with room in every line it uses. Often there are only one or two places it can go, and every cell they share is a segment.
5. Close off the longest ship left. Once a ship is as long as the longest one still to find, water closes it off at both ends. On the large boards, try every way a row can get its segments: a cell they all agree on is settled.

FAQ

Is Hidden Fleet free to play?

Yes. Like every game on Play, it runs free in your browser, with no download and no account needed.

How is it different from Sea Battle?

Sea Battle is the game for two: you fire at the computer's sea and it fires at yours. Hidden Fleet is the puzzle for one: nothing is fired, the numbers and the cells shown give you everything you need, and you work out where the whole fleet lies.

What does a hint do?

It fixes a wrong mark first if there is one; otherwise it places the next segment that follows by logic from the marks on the board, marks the water that step knows about, and the line under the sea says which rule it used. Each hint adds 30 seconds to your time.

What is today's fleet?

Every day everyone plays the same medium 8 by 8 board, so times compare directly on the leaderboard.

How is my score counted?

Your score is the time from the first look at the sea to the last segment in place, plus 30 seconds for every hint. Lower is better.