Puzzle | Four Alternating Knights

There are four knights on a 3 x 3 chessboard. The two white knights are at the two bottom corners, and the two black knights are at the upper two corners of the board.

Find the shortest sequence of moves to achieve the final position as shown in the figure, or prove that no such sequence exists.

Check if you were right - full answer with solution below.

Solution: 

In this matrix, we have two knights of black color, followed by two knights of white color.

A knight in a game of chess has L-shaped moves. So, it can occupy at most two different positions in a single move on a 3 x 3 board.

There are multiple ways to find a path, but only three knights can reach their corroect positions. The fourth knight always gets stuck. Therefore, this puzzle has no solution.