From: "Manabu, Terao" <mt_shogi <at> LYCOS <dot> NE <dot> JP>
Date: 12 aug 1999
Subject: An analysis on dropping pieces

Dear Shogi Fans,

It is our common sense that shogi is a unique game of being able to
drop captured pieces in comparison with other shogi/chess family.
However, it might be difficult to answer the following questions;

  How frequently do we drop pieces in a game?
  Which piece do we drop most in a game?
  Does drop frequency have somthing to do with how exciting a game is?

To find a clue for answering them, I'm trying to make some statistical
analysis regarding the 57th Meijinsen between Sato and Tanigawa in the
charts below. The findings I have are followings;

  * The number of dropping moves cannot exceed the number of captuing
    moves, naturally.
  * The average rate of drop move vs total moves is approx. 20%.
  * The half of the moves of a game are capturing or dropping move.
  * Longer game, higher rate of drop moves vs total moves.
  * Approx. 60% of captured pieces are to be dropped till resignation.
  * The piece that is most frequently dropped is Pawn. It sounds natural
    since Pawns are biggest in quantity. But the rotation of Pawns is
    lower than that of other capturable pieces except Lance. In additon,
    the second is kNight and the third is Bishop. Both have higher
    rotation than Pawn as well as average.
  * Lance has been rarely dropped in the 57th Meijinsen. I think this is
    very exceptional.
  * Every game Pawn and Knight have been dropped.
  * For me, higher rotation, more exciting game.

What do you think?

Manabu Terao


<< Total moves, capturing moves and drop moves >>
        Game 1  Game 2  Game 3  Game 4  Game 5  Game 6  Game 7  Total
Total       66      81      99     100      89     203     103    741
Capture     21      24      25      33      24      61      35    223
Any Drop    10      16      15      19      13      47      22    142
P Drop       5       8       3       6       4      18      10     54
L Drop       0       0       0       0       0       5       0      5
N Drop       3       4       5       2       5       8       2     29
S Drop       1       0       1       1       1       7       3     14
G Drop       0       0       2       1       0       6       1     10
B Drop       0       3       3       7       3       0       4     20
R Drop       1       1       1       2       0       3       2     10

<< Rate of capturing and/or drop moves vs total moves >>
        Game 1  Game 2  Game 3  Game 4  Game 5  Game 6  Game 7  Total
C/T     31.8%   29.6%   25.3%   33.0%   27.0%   30.0%   34.0%   30.1%
D/T     15.2%   19.8%   15.2%   19.0%   14.6%   23.2%   21.4%   19.2%
(C+D)/T 47.0%   49.4%   40.4%   52.0%   41.6%   53.2%   55.3%   49.3%

<< Rate of drop moves vs capturing moves >>
        Game 1  Game 2  Game 3  Game 4  Game 5  Game 6  Game 7  Total
D/C     47.6%   66.7%   60.0%   57.6%   54.2%   77.0%   62.9%   63.7%

<< Rate of drop moves of each pieace / total drop moves
        Game 1  Game 2  Game 3  Game 4  Game 5  Game 6  Game 7  Total
P       50.0%   50.0%   20.0%   31.6%   30.8%   38.3%   45.5%   38.0%
L        0.0%    0.0%    0.0%    0.0%    0.0%   10.6%    0.0%    3.5%
N       30.0%   25.0%   33.3%   10.5%   38.5%   17.0%    9.1%   20.4%
S       10.0%    0.0%    6.7%    5.3%    7.7%   14.9%   13.6%    9.9%
G        0.0%    0.0%   13.3%    5.3%    0.0%   12.8%    4.5%    7.0%
B        0.0%   18.8%   20.0%   36.8%   23.1%    0.0%   18.2%   14.1%
R       10.0%    6.3%    6.7%   10.5%    0.0%    6.4%    9.1%    7.0%

<< Rotation (drop moves / quantity of all capturable pieces(38) or each piece)>>
        Game 1  Game 2  Game 3  Game 4  Game 5  Game 6  Game 7  Total
All     0.26    0.42    0.39    0.50    0.34    1.24    0.58    0.53
P       0.14    0.22    0.08    0.17    0.11    0.50    0.28    0.21
L       0.00    0.00    0.00    0.00    0.00    1.25    0.00    0.18
N       0.75    1.00    1.25    0.50    1.25    2.00    0.50    1.04
S       0.25    0.00    0.25    0.25    0.25    1.75    0.75    0.50
G       0.00    0.00    0.50    0.25    0.00    1.50    0.25    0.36
B       0.00    1.50    1.50    3.50    1.50    0.00    2.00    1.43
R       0.50    0.50    0.50    1.00    0.00    1.50    1.00    0.71

End of this message



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