Single Comment

It seems that the lengthy wins in K+R vs K+WD are mainly due to hunting down a WD that is not able to connect with its King, in combination with an unfavorable black King location (near the edge), which allows you to force separation of them even when they can connect. 

Note that K + R vs royal WD is a win. So there are many wins where K+R drive the WD into a corner. But the longest wins are those where the WD can just survive by fleeing to the shelter of an unfavorably placed King, and then, under the threat of mate, can be forced away from it, to be hunted down in isolation after all. Like in the following game:

[Event 'Computer Chess Game']
[Site 'CHESS_LAPTOP']
[Date '2012.03.02']
[Round '-']
[White 'EGTgen 1.2.4']
[Black 'hgm']
[Result '1-0']
[TimeControl '40/60']
[Variant 'fairy']
[FEN 'K7/7k/2R5/8/8/8/w7/8 w - - 0 1']
[SetUp '1']

{--------------
K . . . . . . .
. . . . . . . k
. . R . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
w . . . . . . .
. . . . . . . .
white to play
--------------}
1. Kb7 {+1000.32/1} Wb2 2. Rd6 {+1000.31/1 0.1} Wc2 3. Kc6 {+1000.30/1 0.1}
We2 4. Kd5 {+1000.29/1 0.1} We3 5. Rb6 {+1000.28/1 0.1} Wg3 6. Ke5
{+1000.27/1 0.1} Wg5 7. Kf4 {+1000.26/1 0.1} Wg6 8. Kf5 {+1000.25/1 0.1}
Wg8 9. Kg5 {+1000.24/1 0.1} Wg7 10. Kh5 {+1000.23/1 0.1} Kg8 11. Rb7
{+1000.22/1 0.1} Kf8 12. Ra7 {+1000.21/1 0.1} We7 13. Kg5 {+1000.20/1 0.1}
We6 14. Kf5 {+1000.19/1 0.1} Wd6 15. Ke5 {+1000.18/1 0.1} Wc6 16. Rd7
{+1000.17/1 0.1} Wc5 17. Kd6 {+1000.16/1 0.1} Wc4 18. Kd5 {+1000.15/1 0.1}
Wc2 19. Rb7 {+1000.14/1 0.1} We2 20. Ke5 {+1000.13/1 0.1} Wf2 21. Rb4
{+1000.12/1 0.1} Wf3 22. Ke4 {+1000.09/1 0.1} Wh3 23. Rb7 {+1000.08/1 0.1}
Wh5 24. Kf4 {+1000.07/1 0.1} Wh4 25. Kf5 {+1000.06/1 0.1} Wh2 26. Rb2
{+1000.05/1 0.1} Wh1 27. Rb1 {+1000.04/1 0.1} Wh2 28. Rf1 {+1000.03/1 0.1}
Wg2 29. Ke4+ {+1000.02/1 0.1} Ke7 30. Kf3 {+1000.01/1 0.1} Wh2 31. Kg3
{+1000.00/1 0.1}
*