The short answer
A knight’s L-shaped jump can pass over another knight. It cannot finish on an occupied square in this non-capturing swap puzzle. Alternate White and Black moves and exchange the two groups’ starting squares.
Set up four knights on a 3 × 3 board
Use files a–c from left to right and ranks 1–3 from bottom to top. White starts on a1 and c1; Black starts on a3 and c3. All five remaining squares are empty. W and B below identify the groups, not different movement rules.
Use these exact rules
- White moves first, then Black; continue alternating.
- Move exactly one knight on each turn using an ordinary L-shaped jump.
- Stay within this three-by-three board.
- Land on an empty square. There are no captures.
- Jumping over pieces is allowed. Do not remove or seal a square after leaving it.
- Finish with White on a3/c3 and Black on a1/c1. Knights of the same colour are interchangeable.
Other puzzles use different board sizes or allow one colour to move repeatedly. Their solutions may not satisfy these rules. Before borrowing a move sequence, check both the starting diagram and the turn rule.
Why jumping is not the same as passing through a square
From a1 the knight has two destinations on this board: b3 and c2. A piece on an imagined intermediate square does not obstruct the jump. A piece on b3 does prevent landing on b3 in this puzzle.
That distinction explains a common failed attempt: moving a knight towards the other row without checking the destination. The aim is not merely to get one knight across. You need to leave enough empty landing squares for the next colour.
Hints before the solution
Hint 1: find the first jump
Try White a1 → c2. Black can then move a3 → b1. Both destinations are empty and the colours have alternated.
Hint 2: do not freeze a knight on its goal
A knight may need to visit a final square, leave it, and return later. Reaching the opposite row once does not mean that knight should never move again.
Hint 3: follow the available landing squares
List the destinations of each knight before moving. On a three-by-three board, the centre b2 is unreachable by a knight from any square on the board. The useful routes run around the outer squares.
A 16-move solution
Try the puzzle before expanding this section. The table records individual moves, not pairs of White/Black turns.
Show the complete worked solution
| Move | Group | Jump |
|---|---|---|
| 1 | White | a1 → c2 |
| 2 | Black | a3 → b1 |
| 3 | White | c1 → b3 |
| 4 | Black | c3 → a2 |
| 5 | White | c2 → a3 |
| 6 | Black | b1 → c3 |
| 7 | White | a3 → b1 |
| 8 | Black | a2 → c1 |
| 9 | White | b3 → a1 |
| 10 | Black | c1 → b3 |
| 11 | White | a1 → c2 |
| 12 | Black | b3 → a1 |
| 13 | White | c2 → a3 |
| 14 | Black | c3 → a2 |
| 15 | White | b1 → c3 |
| 16 | Black | a2 → c1 |
After move 8: White occupies b1/b3, Black c1/c3. After move 12: White b1/c2, Black a1/c3. After move 16: White a3/c3, Black a1/c1. Every landing square is empty when used.
Check a solution yourself
After every jump, update the occupied-square list before considering the other colour. A legal move has coordinate differences of one and two, stays on the board and ends on an empty square. If the final arrangement is right but two consecutive moves belong to White, it is not a solution to this version.
We checked this sequence by enumerating the possible positions and replaying its jumps. You can also reproduce it with four coins on paper. No capture, hidden rule or move outside the diagram is required.
How this differs from Knight Chase
Knight Chase, our Android tactical puzzle, uses a different objective. In a standard duel you capture or trap a rival, and departed squares become sealed. The swap puzzle above leaves squares reusable and does not allow captures. It is a separate exercise, not an advertised mode in the app.
For the underlying movement, read our knight movement guide. To explore changing routes, try the guided Knight Chase trap and its strategy guide. The game is available on Android through Google Play, with ads and optional in-app purchases.