Hello,
Here is the Constellation Expert (5 MHz, year 1985) analysis.
It finds the checkmat in 52 seconds.
Code:
00:00:00 00:00:37 ev=+09.69 d=01-02 01/04 000. c4c5 000004131
00:00:00 00:00:37 ev=+09.69 d=03-04 17/25 000. c4c5 000004393
00:00:00 00:00:37 ev=+09.69 d=04-05 22/25 000. c4c5 000004981
00:00:00 00:00:37 ev=+09.69 d=05-05 25/25 000. c4c5 000006246
00:00:04 00:00:37 ev=+09.69 d=06-08 25/25 000. c4c5 000017221
00:00:15 00:00:37 ev=+09.69 d=07-08 25/25 000. c4c5 000045009
1. d6c7 170678
00:00:52 00:00:37 Mat in 03 d=07-02 08/25 001. .... d4f6 a5a6 f6d8 a6a5 c7b7 000000000
1. .... a6a5 0
00:00:52 00:00:40 Mat in 03 d=07-02 08/25 001. d4f6 a5a6 f6d8 a6a5 c7b7 000000000
2. d4f6 0
00:00:52 00:00:40 Mat in 02 d=07-02 08/25 002. .... f6d8 a6a5 c7b7 000000000
2. .... a5a6 0
00:00:52 00:00:45 Mat in 02 d=07-02 08/25 002. f6d8 a6a5 c7b7 000000000
3. f6d8 0
00:00:52 00:00:45 Mat in 01 d=07-02 08/25 003. .... c7b7 000000000
3. .... a6a5 0
00:00:52 00:00:48 Mat in 01 d=07-02 08/25 003. c7b7 000000000
In infinite level, chekmate in 5 found in half minute.
Code:
00:00:00 00:00:00 ev=+08.79 d=03-08 23/23 000. c8b6 b7a6 b6a4 000013123
00:00:00 00:00:00 ev=+09.41 d=03-05 14/23 000. d6d7 b7b8 c4c5 000013374
00:00:00 00:00:00 ev=+09.41 d=04-07 23/23 000. d6d7 b7b8 c4c5 000013648
00:00:00 00:00:00 ev=+08.75 d=04-08 22/23 000. d6d7 b7a6 c4c5 a6b5 000013854
00:00:00 00:00:00 ev=+08.75 d=05-07 23/23 000. d6d7 000014856
00:00:01 00:00:00 ev=+09.87 d=05-06 22/23 000. d6d7 b7a6 c4c5 a6b5 c5c6 000015583
00:00:01 00:00:00 ev=+09.69 d=01-01 01/25 000. c4c5 000001684
00:00:01 00:00:00 ev=+09.25 d=03-04 22/25 000. c4c5 a6b7 c8b6 000001883
00:00:01 00:00:00 ev=+09.31 d=03-04 10/25 000. d6c6 a6a5 c4c5 000002149
00:00:01 00:00:00 ev=+09.31 d=04-06 25/25 000. d6c6 a6a5 c4c5 000002412
00:00:01 00:00:00 ev=+09.71 d=04-05 24/25 000. d6c6 a6a5 c4c5 a5a6 000002613
00:00:01 00:00:00 ev=+09.94 d=04-03 19/25 000. c4c5 a6b5 c5c6 b5c4 000002801
00:00:02 00:00:00 ev=+09.94 d=05-07 25/25 000. c4c5 a6b5 c5c6 b5c4 000004081
00:00:02 00:00:00 ev=+10.47 d=05-06 24/25 000. c4c5 a6b5 c8b6 b5a5 c5c6 000004779
00:00:06 00:00:00 ev=+10.47 d=06-09 25/25 000. c4c5 a6b5 c8b6 b5a5 c5c6 000015502
00:00:07 00:00:00 ev=+10.02 d=06-07 24/25 000. c4c5 a6b7 c8b6 b7a6 b6a4 a6b5 000017421
00:00:22 00:00:00 ev=+10.02 d=07-10 25/25 000. c4c5 a6b7 c8b6 b7a6 b6a4 a6b5 000049377
00:00:22 00:00:00 ev=+10.02 d=07-08 25/25 000. c4c5 000049563
00:00:26 00:00:00 ev=+15.78 d=07-08 24/25 000. d6c6 000057711
1. d6c6 67844
00:00:30 00:00:00 Mat in 04 d=07-02 24/25 001. .... c8b6 a5a6 b6a8 a6a5 d4b6 a5a6 a8c7 000000000
1. .... a6a5 0
00:00:30 00:00:02 Mat in 04 d=07-02 24/25 001. c8b6 a5a6 b6a8 a6a5 d4b6 a5a6 a8c7 000000000
2. c8b6 0
00:00:30 00:00:02 Mat in 03 d=07-02 24/25 002. .... b6a8 a6a5 d4b6 a5a6 a8c7 000000000
2. .... a5a6 0
00:00:30 00:00:03 Mat in 03 d=07-02 24/25 002. b6a8 a6a5 d4b6 a5a6 a8c7 000000000
3. b6a8 0
00:00:30 00:00:03 Mat in 02 d=07-02 24/25 003. .... d4b6 a5a6 a8c7 000000000
3. .... a6a5 0
00:00:30 00:00:05 Mat in 02 d=07-02 24/25 003. d4b6 a5a6 a8c7 000000000
4. d4b6 0
00:00:30 00:00:05 Mat in 01 d=07-02 24/25 004. .... a8c7 000000000
4. .... a5a6 0
00:00:30 00:00:06 Mat in 01 d=07-02 24/25 004. a8c7 000000000
5. a8c7 0
Another solution for checkmate in 4 :
00:00:00 00:00:00 ev=+09.68 d=03-04 24/24 (a6a5) 000. c8b6 a5a6 b6a4 000008690
00:00:00 00:00:00 ev=+09.71 d=03-04 16/24 (a6a5) 000. d4c3 a5a6 c8b6 a6a7 b6a4 000008887
00:00:00 00:00:00 ev=+09.71 d=04-07 24/24 (a6a5) 000. d4c3 a5a6 c8b6 a6a7 b6a4 000009398
00:00:01 00:00:00 ev=+09.71 d=05-07 24/24 (a6a5) 000. d4c3 a5a6 c8b6 a6a7 b6a4 000010770
00:00:01 00:00:00 ev=+09.66 d=03-04 19/23 (a6a5) 000. c4c5 000000687
00:00:02 00:00:00 ev=+09.66 d=04-05 21/23 (a6a5) 000. c4c5 000001294
00:00:02 00:00:00 ev=+09.66 d=05-06 23/23 (a6a5) 000. c4c5 000002928
00:00:05 00:00:00 ev=+09.66 d=06-08 23/23 (a6a5) 000. c4c5 000012395
1. c4c5 13426
00:00:06 00:00:00 Mat in 03 d=06-02 23/23 (a6a5) 001. .... c6b7 a5b5 c8d6 b5a5 d4c3 000000000
1. .... a6a5 0
00:00:06 00:00:01 Mat in 03 d=06-02 23/23 (a6a5) 001. c6b7 a5b5 c8d6 b5a5 d4c3 000000000
2. c6b7 0
00:00:06 00:00:01 Mat in 02 d=06-02 23/23 (a5b5) 002. .... c8d6 b5a5 d4c3 000000000
2. .... a5b5 0
00:00:06 00:00:03 Mat in 02 d=06-02 23/23 (a5b5) 002. c8d6 b5a5 d4c3 000000000
3. c8d6 0
00:00:06 00:00:04 Mat in 01 d=06-02 23/23 (b5a5) 003. .... d4c3 000000000
3. .... b5a5 0
00:00:06 00:00:06 Mat in 01 d=06-02 23/23 (b5a5) 003. d4c3 000000000
4. d4c3 0
Cordialy,
mychess.