SEE — 3 letters
Trace SEE from row 1, column 4. Move right to row 1, column 5 for E, then turn down to row 2, column 5 for the final E. The route reads S → E → E, uses one right move and one down move, and finishes after three cells. It spans two rows and two columns, so it is a compact opening check rather than a straight run.
For a precise comparison, use this transcript: 1 at row 1, column 4; 2 at row 1, column 5; 3 at row 2, column 5. All three visits are edge cells, including one corner visit at the second position. This is the first route in the displayed length order, assigning three cells and leaving 18 open cells for the remaining answers.