Hartmut Thordsen (Germany)  vs  Mona         Jan 8 - Feb 13, 2001

   1. e1-g3 a4-c2   2. g1-g4 a2-d2   3. f1-f3 a5-c7   4. g3:c7 h7-e4
   5. c7-f4 h6-f6   6. b1-b3 h4-e7   7. d1:h5 a3-d6   8. e8-g6 a6:c8
   9. d8-c7 h2-e2  10. b8-b6 c8:f8  11. g8-g5 f8:f4  12. f3-c3 h3-e3
  13. b3:e3 e7:e3  14. c3:e3 a7:c7  15. h5:e2 c2-f5  16. b6-d4 f6:d4
  17. c1-d1 d2-c3  18. d1:d4 d6:d4  19. e3-g3 c7-c5++

  Hartmut Thordsen is one of the top LoA players in the world.  He won
  the Mind Sports Olympiad gold medal in 1998, and finished third in the
  1999 e-mail tournament (behind Jorge Gómez Arrausi and Kerry Handscomb).
  He tied for first in the toughest preliminary section this year, with
  a 6-1 score including a win over long-time rival Fred Kok (who won the
  MSO gold medal in 1997 and 1999).

  Hartmut has an excellent understanding of positional considerations in
  LoA.  His commentary in this game helped me to better appreciate Mona's
  play, and also taught me more about the game itself.

  Move by Move:

      +-----------------+
    8 | . B B B B B B . |
    7 | W . . . . . . W |
    6 | W . . . . . . W |
    5 | W . . . . . . W |
    4 | W . . . . . . W |
    3 | W . . . . . B W |
    2 | W . . . . . . W |
    1 | . B B B . B B . |
      +-----------------+
        a b c d e f g h  

   1. e1-g3 a4-c2

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . . . . . . W |        7 | W . . . . . . W |
    6 | W . . . . . . W |        6 | W . . . . . . W |
    5 | W . . . . . . W |        5 | W . . . . . . W |
    4 | . . . . . . . W |        4 | . . . . . . B W |
    3 | W . . . . . B W |        3 | W . . . . . B W |
    2 | W . W . . . . W |        2 | W . W . . . . W |
    1 | . B B B . B B . |        1 | . B B B . B . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   2. g1-g4 a2-d2

 ply value  best  principle variation (last 4-ply deleted)

 11     -3  a2-d2 g8-g5 a5-c7 c8-f5 c7:g3 f1-f4 a3-d3
 13    -24  a2-d2 b8-b6 h7-e4 g8-g5 a5-c3 f1-d3 a3:c1 c8-c4 c3-d4

 A note on Mona's minimax scores:

 There is a significant odd-even effect, so odd-ply values are likely
 optimistic (at least 50 points too high, so +50 should be interpreted
 as an equal position).  A score of about +150 usually indicates a
 small advantage, and +300 a clear advantage.

 In these games, Mona indicates a mate threat with a +2000 bonus, so
 a score of +4150 indicates a small positional advantage with a double
 threat to connect.  Only certain types of mate threats are detected
 statically, so there could be more in a given position.  Mona reserves
 0 (zero) for a draw and +32000 for a win.

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . . . . . . W |        7 | W . . . . . . W |
    6 | W . . . . . . W |        6 | W . . . . . . W |
    5 | W . . . . . . W |        5 | W . . . . . . W |
    4 | . . . . . . B W |        4 | . . . . . . B W |
    3 | W . . . . . B W |        3 | W . . . . B B W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . B B B . B . . |        1 | . B B B . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   3. f1-f3 a5-c7

 Hartmut:  My way of playing LoA is quite intuitive -- so I have best
 chances to lose here, since I don't really care for analyzing the next
 moves, as the program necessarily does.  It's more an overall view for
 the present situation, if I will decide for a specific move or another.

 11    +35  a5-c7 c8-f5 a7-d7 b8-a7 h7-h1 g8-g5 h1:f3
 13    +50  a5-c7 b1-b3 a7-d7 d1:h5 h7-e7 f8-f6 c7:g3 b8-a7 a3-c5

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . W . . . . W |        7 | W . B . . . . W |
    6 | W . . . . . . W |        6 | W . . . . . . W |
    5 | . . . . . . . W |        5 | . . . . . . . W |
    4 | . . . . . . B W |        4 | . . . . . . B W |
    3 | W . . . . B B W |        3 | W . . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . B B B . . . . |        1 | . B B B . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   4. g3:c7 h7-e4

 11   +120  h7-e4 g8-f7 h2-e2 f8:h6 a3:c1 h6-e3 h4-f6
 13    +99  h7-e4 g8-f7 a3-c5 d8-b6 h3:f3 b1-b4 c2:c7 f7-f4 h6-e6

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . B . . . . . |        7 | W . . . . . . . |
    6 | W . . . . . . W |        6 | W . . . . . . W |
    5 | . . . . . . . W |        5 | . . . . . . . W |
    4 | . . . . W . B W |        4 | . . . . W B B W |
    3 | W . . . . B . W |        3 | W . . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . B B B . . . . |        1 | . B B B . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   5. c7-f4 h6-f6

 Hartmut:  e4 is not really to attack, and I feared next move h6-e3, so
 this move back is probably the best I can do for now.

 Darse:  It seems inefficient to have moved the same piece three times
 already, but appearances can be deceiving!  Mona is definitely intending
 the capture on c7, and agrees that this is one of Black's best moves.

 11    +98  a7-a4 b1-e1 a4:f4 d1:h5 h2-e2 e1-g3 h4-f6
 11   +108  h6-f6 d8-d5 a7-a4 b1-e1 a4:f4 d1:h5 f6-e5
 13   +112  h6-f6 d8-d5 a3:c1 d5:d2 h3:f3 b8-e5 c1-b2 d2-c3 a6-b5

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . . . . . . . |        7 | W . . . . . . . |
    6 | W . . . . W . . |        6 | W . . . . W . . |
    5 | . . . . . . . W |        5 | . . . . . . . W |
    4 | . . . . W B B W |        4 | . . . . W B B W |
    3 | W . . . . B . W |        3 | W B . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . B B B . . . . |        1 | . . B B . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   6. b1-b3 h4-e7

 Hartmut:  Mona's h6-f6 was expected -- I would have played this move,
 too.  b1-b3 frees f3 from an indirect threat of h3, whenever a3 will
 move (and probably do some other serious threat).  In addition c2 no
 longer reaches f5, where I couldn't beat it.  And I don't see any real
 chance to free b1 c1 d1 behind c2 d2 with a single transaction, so I
 have to work on getting these pieces back into the game right now.

 11   +126  h4-e7 g8-h7 h5-f7 h7:e4 h2-e2 c8-f5 a7-a4
 13   +114  h4-e7 g8-h7 h5-f7 h7:e4 c2:e4 b8-e5 a7-d7 c8:a6 a3-d6

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B B B B . |
    7 | W . . . W . . . |        7 | W . . . W . . . |
    6 | W . . . . W . . |        6 | W . . . . W . . |
    5 | . . . . . . . W |        5 | . . . . . . . B |
    4 | . . . . W B B . |        4 | . . . . W B B . |
    3 | W B . . . B . W |        3 | W B . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . . B B . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   7. d1:h5 a3-d6

 Hartmut:  Mona's move h4-e7 was expected, too.  I couldn't move away
 with d8 without losing important positions in the middle, so I had to
 live with these last two moves.  Now it's time to find some new idea
 and take the initiative in this game.  I'd like to play 7. b8-e5, but
 after h5-f5 it wouldn't be better than before.  h5 has to be black!
 If Mona takes it back with h2, at least the threat h2-e2 is gone.

 Darse:  Mona switches away from the re-capture, near the end of the
 one billion node search, and by only one point.

 13   +127  h2:h5 f8-g7 a7-d7 f3:f6 a6-c6 g8-g5 a3-c5 c1-b2 h5-f7
 13   +128  a3-d6 g8-h7 a7-d7 h7:e7 e4:e7 b8-a7 d7-d3 a7-c7 h2-e2

      +-----------------+          +-----------------+
    8 | . B B B B B B . |        8 | . B B B . B B . |
    7 | W . . . W . . . |        7 | W . . . W . . . |
    6 | W . . W . W . . |        6 | W . . W . W B . |
    5 | . . . . . . . B |        5 | . . . . . . . B |
    4 | . . . . W B B . |        4 | . . . . W B B . |
    3 | . B . . . B . W |        3 | . B . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   8. e8-g6 a6:c8

 Hartmut:  If I play 8. g8-h7, it prepares my next move c8-f5, while h5
 is still mine.  I'd expect a6:c8 and the game would become a hard fight.
 So the middle isn't already mine.  Playing 8. c8-f5 directly doesn't
 work after h2:h5 -- I cannot keep my position at f5.  8. e8-g6 seems
 to be best (at least better than the two already mentioned).  I have a
 stronger influence on the focus spot e6, and allowing h2:h5 will give
 a strong block with g8-g5.  a6:c8 is still a good move, but I can now
 answer with g8-e6.

 Darse:  Hartmut's analysis is definitely in harmony with Mona's, and
 helps me understand her moves much better than I normally do.  Mona's
 principle variation reply was g8-h7, which might be showing the more
 short-term thinking typical of computer programs.  Hartmut's move
 may be better, but the e6 focal point is possibly too vague for her.
 Another interesting possibility which showed up in YL's analysis is
 8. b8-h8, intending h8:f6.  The programs have a natural bias against
 corner moves, so it probably has some merit.

 11   +235  a6:c8 g6-g3 a7-c7 g8-g5 h2:h5 b8-b6 h5-g6
 13   +217  a6:c8 f8-g7 a7-d7 f3:f6 c8:g4 b3-d5 h2:h5 g8:g4 e7-e5

      +-----------------+          +-----------------+
    8 | . B W B . B B . |        8 | . B W . . B B . |
    7 | W . . . W . . . |        7 | W . B . W . . . |
    6 | . . . W . W B . |        6 | . . . W . W B . |
    5 | . . . . . . . B |        5 | . . . . . . . B |
    4 | . . . . W B B . |        4 | . . . . W B B . |
    3 | . B . . . B . W |        3 | . B . . . B . W |
    2 | . . W W . . . W |        2 | . . W W . . . W |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

   9. d8-c7 h2-e2

 Hartmut:  b8 and d8 are now in a poor location, so I must work on this.
 After another move of Mona like a7-c7, b8 wouldn't look better.  I can
 now move b8-b6 (allowing d8 to move to h8 again) or d8-c7, hindering
 a7-c7.  The first one seems mandatory, since it also handles the threat
 d6:g6.  Problem: h2:h5 would cause another threat d6:f4. :-(((
 If 9. d8-c7, take the (hopefully poison) d6:g6, b8-b6 brings those two
 stones efficiently back into play -- with the price of getting problems
 at f8 and g8, but this seems to be less difficult than before. I think
 I do this now.

 Darse:  Mona was quite definite about h2-e2.  Apart from any immediate
 tactics, I like seeing her bring another outlier into the fold.  The
 e2 piece now guards e6, and the h3 piece still exerts pressure on h5.

 11   +268  h2-e2 b8-b6 c8:f8 b6-b4 h3:h5 b4:d2 e2-e5
 13   +240  h2-e2 g8:c8 h3:h5 b8-b6 f6:b6 c1-b2 a7-c5 c7:e7 e2-d3

      +-----------------+          +-----------------+
    8 | . B W . . B B . |        8 | . . W . . B B . |
    7 | W . B . W . . . |        7 | W . B . W . . . |
    6 | . . . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . . B |        5 | . . . . . . . B |
    4 | . . . . W B B . |        4 | . . . . W B B . |
    3 | . B . . . B . W |        3 | . B . . . B . W |
    2 | . . W W W . . . |        2 | . . W W W . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  10. b8-b6 c8:f8

 Hartmut.  I thought Mona would rather play d6:g6... I shouldn't tell
 you too much about my play. ;-)  I'd now like to do two moves at once:
 b8-b6 and g8-g5.  I decide for the first.  It hinders d6 to beat g6 and
 blocks a7 (after a7-b6 the figure left on b8 would cause some problems).

 11   +244  c8:f8 h5-f7 f8-c5 g8-g5 d2-d4 c1-b2 e2-d3
 13   +283  c8:f8 h5-f7 a7-a8 g8-d5 d2:d5 c1-e3 e7:e3 b3-b5 d5:b5

      +-----------------+          +-----------------+
    8 | . . . . . W B . |        8 | . . . . . W . . |
    7 | W . B . W . . . |        7 | W . B . W . . . |
    6 | . B . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . . B |        5 | . . . . . . B B |
    4 | . . . . W B B . |        4 | . . . . W B B . |
    3 | . B . . . B . W |        3 | . B . . . B . W |
    2 | . . W W W . . . |        2 | . . W W W . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  11. g8-g5 f8:f4

 Hartmut:  The last move was strong with the double-threat along the
 f-line f8:f4 and later f6:f3.  I remember I saw this when studying the
 situation before my last move, but it seems I ignored it a few minutes
 later when deciding on my move.  It's too bad, but it seems I MUST
 answer this strongest threat by Mona in the game so far, and there is
 only one move to do so.  But after h5-f7, Mona will play c2-f5 -- what
 else?  Then I will never get back into the middle, and my important
 figures at f4 and g6 are still easy to beat, when I move c1 and b6.
 I think the game is lost right here and now. :-(  Let me resign later.
 Even if I don't see a big chance to win now, I will try a different way
 than the one described above.

 Darse:  The double threat along the f-file explains why the PV move was
 g8:c8 (however, b8-b6 was the 11-ply reply, and the score didn't change
 much, so it must also be a pretty good move).  11. h5-f7 was indeed the
 expected move.  There are two or three possible follow-up moves, but
 Mona would likely try to control f5, if not occupying it immediately.
 All moves other than 11. h5-f7 are viewed as some concession, but she
 certainly doesn't think the game is over!  (Of course, Hartmut can see
 further into the future than the program can, in terms of strategy).

 11   +317  f8:f4 h5-f5 e7-c5 b6-b4 c5:f5 b4:d2 h3-g2
 13   +405  f8:f4 h5-f5 e2-e5 c1-b2 f6:b6 g5:e7 b6-d4 c7-b6 d2-d5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | W . B . W . . . |        7 | W . B . W . . . |
    6 | . B . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . B B |        5 | . . . . . . B B |
    4 | . . . . W W B . |        4 | . . . . W W B . |
    3 | . B . . . B . W |        3 | . B B . . . . W |
    2 | . . W W W . . . |        2 | . . W W W . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  12. f3-c3 h3-e3

 Hartmut:  No very new thoughts about the game here.  h5-f5 seems
 mandatory, but e2-e5 would follow, and c1 is still bound by the attack
 d2:g5.  b3-e3 helps in this case, but f6:f3 would break up my little
 cluster.  It's all too much -- I need to be able to move twice while
 Mona sleeps...  All moves I think about show some significant kind of
 despair. :-(  Let's try f3-c3, but there is more than just one good
 move for Mona to answer.

 Darse:  Mona now agrees that c2-f5 gives White a large positional edge,
 but she switches to h3-e3 because it ensures a connection threat.

 13   +629  c2-f5 g6-g3 e2-e5 h5-f3 a7-b8 b6-d8 b8-b6 b3-a4 b6-c5
 13  +2061  h3-e3 g5-e5 e7-g5 c1-b2 e4-f3 g4-f5 e2:e5 b6:e3 a7-c5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | W . B . W . . . |        7 | W . B . W . . . |
    6 | . B . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . B B |        5 | . . . . . . B B |
    4 | . . . . W W B . |        4 | . . . . W W B . |
    3 | . B B . W . . . |        3 | . . B . B . . . |
    2 | . . W W W . . . |        2 | . . W W W . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  13. b3:e3 e7:e3

 Hartmut:  :-(((

 Darse:  That was the best try, but Mona now sees at least a double mate
 threat on the horizon.  I'm afraid it looks like Hartmut's assessment
 from several moves ago was correct.

 11  +2304  e7:e3 c3:e3 e2-d3 c7-e7 f6:b6 e7:e4 a7-d4
 13  +4378  e7:e3 c3:e3 a7:c7 g5-g2 d6-c5 g2:e4 c7-c3 e3:c3 e2-d3

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | W . B . . . . . |        7 | W . B . . . . . |
    6 | . B . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . B B |        5 | . . . . . . B B |
    4 | . . . . W W B . |        4 | . . . . W W B . |
    3 | . . B . W . . . |        3 | . . . . B . . . |
    2 | . . W W W . . . |        2 | . . W W W . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  14. c3:e3 a7:c7

 Hartmut:  The only move to win some time, but nothing more...

 Darse:  Yes, it is the only move that pushes the mate to 13-ply, but
 Mona is now able to see to the end of the game.

 Despite the loss, it is clear to me why Hartmut is one of the elite
 players in this game (his own modesty notwithstanding).  The depth of
 positional understanding he's demonstrated is something that computer
 programs can only aspire to, regardless of their short-term expertise.

 I want to thank Hartmut again for his insightful commentary during the
 game, which not only gave me something to learn from, but also helped
 me to appreciate the play of my protégée on a whole new level.

 11  +4378  a7:c7 g5-g2 d6-c5 g2:e4 c7-c3 e3:c3 e2-d3 e4-e5 c5-e3 e5:e3 f6-d4
 13 +32000  a7:c7 g5-g2 d6-c5 g2:e4 c7-c3 e3:c3 e2:e4 h5-f3 f6:f3 c1-b1 c2-e2 b1:e4 c5:c3

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | . . W . . . . . |        7 | . . W . . . . . |
    6 | . B . W . W B . |        6 | . B . W . W B . |
    5 | . . . . . . B B |        5 | . . . . . . B . |
    4 | . . . . W W B . |        4 | . . . . W W B . |
    3 | . . . . B . . . |        3 | . . . . B . . . |
    2 | . . W W W . . . |        2 | . . W W B . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  15. h5:e2 c2-f5

 Hartmut:  Thanks for all the nice words.  If it's not too much work
 on your side I will likely play with Mona again after the tournament.
 For now let's see if the game runs as expected [about five moves each]
 to the end...

 Hartmut:  I can live with the fact that a number-crunching piece of
 silicon can beat me.  I think this is a well-known feeling all of us
 have got to know in the past against a few-dollar-chesscomputer.  So
 what is new about it in LoA?  I would still be proud if I could be
 second in the end, but the best human player in the field.

 Darse:  I agree.  Some games are just naturally suited for computers.
 I wrote an Awari program a couple of years ago that could beat any
 human that ever lived, practically the first day it started searching.
 So what?  LoA is a much bigger challenge, but there is no disgrace in
 losing to a strong program.  Should we feel bad if we cannot lift as
 much weight as a fork lift?

  9 +32000  c2-f5 b6-d4 f6:d4 c1-d1 d2-c3 d1:d4 d6:d4 e3:c3 c7-e5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | . . W . . . . . |        7 | . . W . . . . . |
    6 | . B . W . W B . |        6 | . . . W . W B . |
    5 | . . . . . W B . |        5 | . . . . . W B . |
    4 | . . . . W W B . |        4 | . . . B W W B . |
    3 | . . . . B . . . |        3 | . . . . B . . . |
    2 | . . . W B . . . |        2 | . . . W B . . . |
    1 | . . B . . . . . |        1 | . . B . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  16. b6-d4 f6:d4

  7 +32000  f6:d4 c1-d1 d2-c3 d1:d4 d6:d4 e3:c3 c7-e5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | . . W . . . . . |        7 | . . W . . . . . |
    6 | . . . W . . B . |        6 | . . . W . . B . |
    5 | . . . . . W B . |        5 | . . . . . W B . |
    4 | . . . W W W B . |        4 | . . . W W W B . |
    3 | . . . . B . . . |        3 | . . . . B . . . |
    2 | . . . W B . . . |        2 | . . . W B . . . |
    1 | . . B . . . . . |        1 | . . . B . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  17. c1-d1 d2-c3

 Hartmut:  The game runs the expected way, for the third move in a row
 by Mona.  (The rest is: d2-c3, d1-d4, d6-d4, e3-g3, c7-c5 and I would
 only need to make one more move to connect, but it's over)

 Darse:  Sometimes these final moves don't look very "natural", because
 there may be more than one way to mate in the given number of moves,
 and the program just takes the first one it finds.  However, in this
 case she agrees with Hartmut almost exactly.

  5 +32000  d2-c3 d1:d4 d6:d4 e3:c3 c7-e5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | . . W . . . . . |        7 | . . W . . . . . |
    6 | . . . W . . B . |        6 | . . . W . . B . |
    5 | . . . . . W B . |        5 | . . . . . W B . |
    4 | . . . W W W B . |        4 | . . . B W W B . |
    3 | . . W . B . . . |        3 | . . W . B . . . |
    2 | . . . . B . . . |        2 | . . . . B . . . |
    1 | . . . B . . . . |        1 | . . . . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  18. d1:d4 d6:d4

  3 +32000  d6:d4 e3:c3 c7-e5

      +-----------------+          +-----------------+
    8 | . . . . . . . . |        8 | . . . . . . . . |
    7 | . . W . . . . . |        7 | . . W . . . . . |
    6 | . . . . . . B . |        6 | . . . . . . B . |
    5 | . . . . . W B . |        5 | . . . . . W B . |
    4 | . . . W W W B . |        4 | . . . W W W B . |
    3 | . . W . B . . . |        3 | . . W . . . B . |
    2 | . . . . B . . . |        2 | . . . . B . . . |
    1 | . . . . . . . . |        1 | . . . . . . . . |
      +-----------------+          +-----------------+
        a b c d e f g h              a b c d e f g h  

  19. e3-g3 c7-c5++

  1 +32000  c7-c5

      +-----------------+
    8 | . . . . . . . . |
    7 | . . . . . . . . |
    6 | . . . . . . B . |
    5 | . . W . . W B . |
    4 | . . . W W W B . |
    3 | . . W . . . B . |
    2 | . . . . B . . . |
    1 | . . . . . . . . |
      +-----------------+
        a b c d e f g h