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Advanced Backgammon part 24D ROLLOUT

Posted By: Matt Cohn-Geier
Date: Wednesday, 1 July 2009, at 5:53 p.m.

In Response To: Advanced Backgammon part 24D (Matt Cohn-Geier)

Robertie's claim is that "stripping the 6-5 combination is correct, but stripping the 5-4 is a mistake".

Position 240A:

Here 5/4 is clear. The alternatives leave Blue odd and with a gapped point which is a bad combination.

Move number 7: Blue to play 61

White	174
Blue	60
Position ID: sNsCFDju7g4AAA Match ID: QQkHAAAAAAAA

• Blue moves 6/off 5/4

#		Ply	Move	Equity
•	1	R	6/off 5/4	+1.1370
			0.7765 0.5923 0.1034 - 0.2235 0.0000 0.0000 +1.2487 +1.1370 0.0013 0.0012 0.0010 - 0.0013 0.0000 0.0000 0.0035 0.0058
			Full cubeful rollout with var.redn.
			5184 games, Mersenne Twister dice gen. with seed 819398175 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	6/off 4/3	+1.0680 ( -0.0690)
			0.7591 0.5720 0.1000 - 0.2409 0.0000 0.0000 +1.1902 +1.0680 0.0040 0.0043 0.0036 - 0.0040 0.0000 0.0000 0.0101 0.0138
			Full cubeful rollout with var.redn.
			354 games, Mersenne Twister dice gen. with seed 819398175 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Position 240B:

5/4 still best even though 3/2 can be played which doesn't leave an inner gap.

Move number 6: Blue to play 61

White	174
Blue	61
Position ID: sNsCFDj27g4AAA Match ID: QQkHAAAAAAAA

• Blue moves 6/off 5/4

#		Ply	Move	Equity
•	1	R	6/off 5/4	+1.1624
			0.7843 0.5947 0.1083 - 0.2157 0.0000 0.0000 +1.2715 +1.1624 0.0011 0.0012 0.0010 - 0.0011 0.0000 0.0000 0.0029 0.0039
			Full cubeful rollout with var.redn.
			5184 games, Mersenne Twister dice gen. with seed 819398175 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	6/off 3/2	+1.1212 ( -0.0411)
			0.7727 0.5829 0.1041 - 0.2273 0.0000 0.0000 +1.2323 +1.1212 0.0022 0.0021 0.0019 - 0.0022 0.0000 0.0000 0.0053 0.0072
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 819398175 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	3	R	6/off 4/3	+1.0291 ( -0.1333)
			0.7471 0.5559 0.1034 - 0.2529 0.0000 0.0000 +1.1535 +1.0291 0.0037 0.0042 0.0031 - 0.0037 0.0000 0.0000 0.0097 0.0126
			Full cubeful rollout with var.redn.
			483 games, Mersenne Twister dice gen. with seed 819398175 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Position 240C:

Despite the fact that Blue has cleared his 6 point, it's still right to strip, pay off to the double shot, and avoid the double jeopardy.

Move number 5: Blue to play 15

White	174
Blue	45
Position ID: sNsCFDju3QEAAA Match ID: QYkUAAAAAAAA

• Blue moves 5/off 3/2

#		Ply	Move	Equity
•	1	R	5/off 4/3	+1.2336
			0.7959 0.6298 0.1127 - 0.2041 0.0000 0.0000 +1.3344 +1.2336 0.0021 0.0022 0.0020 - 0.0021 0.0000 0.0000 0.0057 0.0071
			Full cubeful rollout with var.redn.
			1804 games, Mersenne Twister dice gen. with seed 862146851 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	5/off 3/2	+1.1992 ( -0.0343)
			0.7908 0.6194 0.1103 - 0.2092 0.0000 0.0000 +1.3114 +1.1992 0.0021 0.0020 0.0020 - 0.0021 0.0000 0.0000 0.0057 0.0076
			Full cubeful rollout with var.redn.
			1803 games, Mersenne Twister dice gen. with seed 862146851 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Messages In This Thread

• Advanced Backgammon part 24D
  Matt Cohn-Geier -- Monday, 29 June 2009, at 7:06 p.m.
  • Advanced Backgammon part 24D
    Marty Storer -- Tuesday, 30 June 2009, at 12:03 p.m.
  • Advanced Backgammon part 24D
    neilkaz -- Tuesday, 30 June 2009, at 2:32 p.m.
  • Robertie's picks
    Matt Cohn-Geier -- Tuesday, 30 June 2009, at 11:29 p.m.
    • Robertie's picks
      Marty Storer -- Wednesday, 1 July 2009, at 3:06 p.m.
  • Advanced Backgammon part 24D ROLLOUT
    Matt Cohn-Geier -- Wednesday, 1 July 2009, at 5:53 p.m.