Fig. 17 shows the most unfavourable position for White's two Rooks. The
shortest way to checkmate the Black King is as follows:
{418}
WHITE. BLACK.
1. R to K sq. 1. K to Q 5
2. R (Kt sq.) to Q sq.: ch. 2. K to B 6
3. R to K 2 3. K to B
4. R to B 2: ch. 4. K to Kt 6
5. R to B 8 5. K to R 6
6. R to Q Kt sq. 6. K to R 5
7. R to R 8, mate.