No, a single checker cannot capture a king in checkers. Here's why:
Kings move diagonally forward and backward, giving them far more flexibility than regular checkers, which only move forward.
To capture a piece, you must jump over it diagonally and land on the empty square immediately beyond. A single checker cannot jump over a king and land on a vacant square behind it because the king's backward movement allows it to avoid such traps.
A lone checker lacks the coordination to force a king into a position where it can be jumped.
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