To move the piece numbered 10 to the empty position \(x\), the sequence of moves required is as follows:
1. Move adjacent pieces systematically to free up the path for the piece numbered 10.
2. Considering the current configuration, a total of 13 moves is required to slide the piece numbered 10 into the empty position \(x\).
Each move shifts one piece either horizontally or vertically toward its target position, ensuring that the empty slot \(x\) is aligned with the desired path.
Conclusion: The least number of moves required is 13.