Nigel Richards - One-in-the-bag pre-endgame analysis (CSW07)

Moves with equal percentages of wins, losses and draws are sorted descendingly according to the following heuristic:

H := (points scored with the move) + (mathematical expectation of the player's highest score next turn) - (mathematical expectation of the opponent's highest score next turn)

While this heuristic is generally good, the ordering according to it should be taken with a grain of salt; for selected examples, we give a better sub-ranking of the moves according to the mathematical expectation of the final spread of the game.

Example 1

This example between Nigel Richards and John O’Laughlin is taken from here. Nigel had a 22 points deficit.
His rack: ?AENNTU
Unseen tiles from his point of view: AAEEIILQ
Game in gcg format

Game board

Nigel played [ENAUNTEr B4 61] which would have lost him the game had he drawn the Q. Indeed, in that case, John could have won the game by 34 points by playing the following sequence of moves with no possible reply from Nigel: [ER H13 2 AAEIIL], [LA 15G 17 AEII], [IF 7G 10 AEI], [YA 6F 9 EI], [DE O13 3 I] and [DEI O13 12].

Our analysis shows that there were four non-losing moves, three of them winning:

Move H W-L-D Wins Losses Draws
[UT 6C 2 ?AENNT] 46.250 8-0-0 +A +E +I +L +Q
[UR 7C 3 ?AENNT] 44.875 8-0-0 +A +E +I +L +Q
[AUNT C6 16 ?EN] 14.125 8-0-0 +A +E +I +L +Q
[NAE 5B 9 ?ENTU] 22.750 7-0-1 +A +E +I +L +Q

Example 2

This example between Pakorn Nemitrmansuk and Nigel Richards is taken from here. Pakorn had a 22 points deficit.
His rack: ?DLRSTU
Unseen tiles from his point of view: ABDEEOOO
Game in gcg format

Game board

Pakorn played [SOD I1 6 ?LRSTU] and won the game.

Our analysis shows that exactly three moves were winning no matter what letter Pakorn would have picked:

Move H W-L-D Wins Losses Draws
[OR 12L 2 ?DLSTU] 46.625 8-0-0 +A +B +D +E +O
[OD 12L 3 ?LRSTU] 44.875 8-0-0 +A +B +D +E +O
[SOD I1 6 ?LRSTU] 44.625 8-0-0 +A +B +D +E +O

Example 3

This example between Pakorn Nemitrmansuk and Nigel Richards is taken from here. Pakorn had a 44 points deficit.
His rack: ?GINNWX
Unseen tiles from his point of view: AEIILOTT
Game in gcg format

Game board

Pakorn played [DRENCHING 15G 48 ?NWX] which would have lost him the game had he drawn the O for example. Indeed, in that case, the optimal endgame sequence would have given Nigel a 3 points win: [ILEA N5 16 ITT] followed by [Xi L3 36 NOW] and [TITE F5 15].

Our analysis shows that one move, and only one, was winning no matter what letter Pakorn would have picked: [WING L3 46 ?NX].

Here are the moves that didn't lose all the time:

Move H W-L-D Wins Losses Draws
[WING L3 46 ?NX] 75.000 8-0-0 +A +E +I +L +O +T
[WaX N4 58 GINN] 71.625 6-2-0 +A +E +L +O +T +I
[WeX N4 58 GINN] 71.625 6-2-0 +A +E +L +O +T +I
[NIX N4 54 ?GNW] 65.375 6-2-0 +A +I +O +T +E +L
[DRENCHING 15G 48 ?WX] 72.250 5-3-0 +A +E +I +L +O +T
[WINN L3 43 ?GX] 71.375 5-3-0 +A +E +I +L +O +T
[EWkING L1 48 NX] 63.375 5-3-0 +A +E +I +O +L +T
[WIG L3 39 ?NNX] 68.000 4-4-0 +A +E +I +L +O +T
[NIXe N4 55 GNW] 47.125 4-4-0 +A +I +O +E +L +T
[GINN L3 39 ?WX] 73.250 3-3-2 +A +E +L +O +T +I
[ENdING L1 42 WX] 59.875 2-5-1 +A +E +I +L +T +O
[EaNING L1 42 WX] 59.875 2-5-1 +A +E +I +L +T +O
[ENrING L1 42 WX] 59.875 2-5-1 +A +E +I +L +T +O
[ENsIGN L1 42 WX] 59.875 2-5-1 +A +E +I +L +T +O
[ErNING L1 42 WX] 59.875 2-5-1 +A +E +I +L +T +O
[INN L4 35 ?GWX] 69.250 2-6-0 +A +E +I +L +O +T
[DRENCHiNG 15G 45 IWX] 66.125 2-6-0 +A +E +I +L +O +T
[NiX N4 52 GINW] 65.625 2-6-0 +A +O +E +I +L +T
[WIN L3 36 ?GNX] 65.000 2-6-0 +A +E +I +L +O +T
[WiNG L3 42 INX] 72.000 1-6-1 +E +A +I +L +T +O
[ENWINd L1 44 GX] 59.250 1-6-1 +O +E +I +L +T +A
[WiNN L3 39 GIX] 67.750 1-7-0 +E +A +I +L +O +T
[GiNN L3 35 IWX] 65.125 1-7-0 +E +A +I +L +O +T
[WiG L3 35 INNX] 65.000 1-7-0 +E +A +I +L +O +T
[Xu N6 50 GINNW] 63.625 1-7-0 +A +E +I +L +O +T
[Xi N6 50 GINNW] 63.625 1-7-0 +A +E +I +L +O +T
[XI N6 52 ?GNNW] 63.375 1-7-0 +A +E +I +L +O +T
[eX N5 49 GINNW] 62.625 1-7-0 +A +E +I +L +O +T
[aX N5 49 GINNW] 62.625 1-7-0 +A +E +I +L +O +T
[WiN L3 32 GINX] 62.000 1-7-0 +E +A +I +L +O +T
[WIGs L3 43 NNX] 58.750 1-7-0 +E +A +I +L +O +T
[WInG L3 43 NNX] 58.750 1-7-0 +E +A +I +L +O +T
[GIN L3 32 ?NWX] 66.250 0-6-2 +I +L +O +T +A +E
[iNN L4 31 GIWX] 61.125 0-7-1 +A +I +L +O +T +E
[TWiNING M1 24 X] 25.875 0-7-1 +E +I +L +O +T +A
[TWINiNG M1 24 X] 25.875 0-7-1 +E +I +L +O +T +A

Example 4

This example between Nigel Richards and Chollapat Itthi-aree is taken from here. Chollapat had a 35 points deficit.
His rack: ?DNOOWX
Unseen tiles from his point of view: AACEFFTU
Game in gcg format

Game board

Chollapat played [WOX 3C 44 ?DNO] that drew if he picked the U and lost otherwise.

Here are the moves that didn't lose all the time:

Move H W-L-D Wins Losses Draws
[aXON K5 46 DOW] 36.375 5-3-0 +A +F +T +C +E +U
[WOX O6 46 ?DNO] 35.250 4-3-1 +C +F +T +A +U +E
[WOOD 3B 28 ?NX] 30.250 4-4-0 +A +E +T +C +F +U
[DOXy 3C 44 NOW] 49.500 3-4-1 +A +E +C +F +U +T
[WEX 13A 44 ?DNOO] 42.250 3-5-0 +A +E +C +F +T +U
[DHOWs 12A 27 NOX] 37.500 3-5-0 +A +E +C +F +T +U
[sHOWD 12A 25 NOX] 35.500 3-5-0 +A +E +C +F +T +U
[DOWN O6 29 ?OX] 32.625 3-5-0 +A +C +E +F +T +U
[JOWeD D2 30 NOX] 30.625 3-5-0 +A +E +C +F +T +U
[WOON O6 28 ?DX] 30.000 3-5-0 +A +E +C +F +T +U
[WOON 3B 25 ?DX] 27.500 3-5-0 +A +E +C +F +T +U
[WOlD 3C 30 NOX] 29.500 2-5-1 +A +C +F +T +U +E
[WOaD 3C 30 NOX] 29.500 2-5-1 +A +C +F +T +U +E
[WOrD 3C 30 NOX] 28.750 2-5-1 +A +C +F +T +U +E
[WOOD O6 31 ?NX] 31.750 2-6-0 +A +C +E +F +T +U
[WOlD O6 28 NOX] 29.000 2-6-0 +A +C +E +F +T +U
[WOaD O6 28 NOX] 29.000 2-6-0 +A +C +E +F +T +U
[WOrD O6 28 NOX] 29.000 2-6-0 +A +C +E +F +T +U
[WOoD O6 28 NOX] 29.000 2-6-0 +A +C +E +F +T +U
[WoOD O6 27 NOX] 28.000 2-6-0 +A +C +E +F +T +U
[DOWp O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWd O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWl O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWf O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWs O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWt O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DOWn O6 26 NOX] 27.000 2-6-0 +A +C +E +F +T +U
[DhOW O6 25 NOX] 26.000 2-6-0 +A +C +E +F +T +U
[gOWD O6 24 NOX] 25.000 2-6-0 +A +C +E +F +T +U
[dOWD O6 24 NOX] 25.000 2-6-0 +A +C +E +F +T +U
[DHOW 12A 26 ?NOX] 40.000 1-7-0 +E +A +C +F +T +U
[NOO C10 15 ?DWX] 25.625 1-7-0 +E +A +C +F +T +U
[WoOD 10D 17 NOX] 25.375 1-7-0 +E +A +C +F +T +U
[WOX 3C 44 ?DNO] 38.625 0-7-1 +A +C +E +F +T +U
[sNOW K5 31 DOX] 30.375 0-7-1 +A +C +E +F +T +U
[aNOW K5 31 DOX] 30.375 0-7-1 +A +C +E +F +T +U
[WON 3C 23 ?DOX] 25.250 0-7-1 +A +C +F +T +U +E

Example 5

This example between Nigel Richards and Jakkrit Klaphajone is taken from here. Scores were even and it was Jakkrit's turn.
His rack: BEERTUU
Unseen tiles from his point of view: ADILLOVW
Game in gcg format

Game board

Jakkrit won the game by playing the only winning move: [TUQUE 3I 30 BER]. The five best moves were:

Move H W-L-D Wins Losses Draws
[TUQUE 3I 30 BER] 25.750 8-0-0 +A +D +I +L +O +V +W
[URUBU 4I 14 EET] 2.125 6-2-0 +A +D +L +V +W +I +O
[BUBU 6D 8 EERT] -2.750 6-2-0 +A +D +L +V +W +I +O
[BRUTE N2 24 EU] 14.125 5-1-2 +A +D +L +O +V +I +W
[RUBE N3 16 ETU] 6.875 5-2-1 +A +D +I +L +V +W +O

Example 6

This example between Hubert Wee and Nigel Richards is taken from here. Nigel had a 15 points deficit.
His rack: ?ARRSTU
Unseen tiles from his point of view: AAEFIIJX
Game in gcg format

Game board

Nigel played [ROT 9M 9 ?ARSU], picked the X and lost the endgame. He was unlucky, as the move he played was one of the only two that lost only one eighth of the time:

Move H W-L-D Wins Losses Draws
[ROT 9M 9 ?ARSU] 5.875 7-1-0 +A +E +F +I +J +X
[RITTS 13I 17 ?ARU] 4.000 7-1-0 +A +E +F +I +J +X

The move [ROT 9M 9 ?ARSU] that Nigel played is actually best according to the mathematical expectation of the final spread of the game. Here are the final spreads of the game from Nigel's point of view after each pick (hover over a spread to see an optimal endgame sequence):

Move A (2) E F I (2) J X Min Max 𝔼[final spread]
[ROT 9M 9 ?ARSU] +8 +11 +9 +9 +9 -10 -10 +11 +6.625
[RITTS 13I 17 ?ARU] +1 +5 +21 +5 +3 -4 -4 +21 +4.625

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