Wei Qi Boards
The rule of surrounding and capturing remain essentially unchanged throughout history,
but the board had evolved. Nowadays, Weiqi boards are 19 x 19. But boards unearthed
in China suggested that early boards were smaller. A board from the Liao Dynasty discovered
in 1977 in Inner Mongolia is 13 x 13. On the other hand, a 17 x 17 board from Han Dynasty
(25A.D.-220A.D.) was unearthed in WangDu, Hebei in 1954. A 17 x 17 board is also seen in
an ancient painting, Tang Lady Playing Go, unearthed in Xin Jiang. In 1971, a 19 x 19 boardfrom
the Sui Dynasty (581 - 618 A.D.) was unearthed in An Yang of Hunan.
Although the number of grids is different on these ancient boards,
it's always an odd number. There are two possible reasons for this.
First of all, odd number grids can prevent tie games. Second, in early days
(dating back to prehistoric times) the Chinese were known to start the game
by playing in the center of the board; and this is only possible with odd number grids.
From the development of Weiqi throughout history, one can conclude that 17x17 and 19x19
boards were most popular. Two literatures during the NanBei Dynasty, YiJing and
DuQuGe both mentioned 17 x 17 boards, indicating that it was quite popular at that
time. Even today, 17 x 17 boards can still be seen in Tibet and XiJin.
The earliest
19 x 19 board unearthed to date is the porcelain table of Sui Dynasty (581-618 A.D.)
found in Hunan. However, SunZi Suan Jing of DongHan (or BeiZhou) alluded to a 19 x 19
board, thus it is possible that 19 x 19 boards were invented as early as the Han Dynasty
(time of Christ).
Comparing the two board sizes, 19 x 19 is more scientific. First of all,
it allows a balance of territory between the third and the fourth lines. For example, if
White takes the outward influence by playing his stones on the fourth line along each side
to form a square, and Black gets the real territory by playing on the third line around
the board. White forms 169 points of territory with 48 stones for an efficiency of 3.52 points
per stone, and Black gets 192 points with 56 stones for an efficiency of 3.43 points per stone.
The stone efficiencies (3.52~3.43) are very close.
The same cannot be said on a 17 x 17 board.
White gets 121 points with 40 stones for an efficiency of 3.03 points per stone, and Black gets
168 points with 48 for an efficiency of 3.5 points per stone. In other words, it is much more
beneficial to crawl along the third line on a 17 x 17 board because the stone efficiency of
getting real territory is larger than that of taking the outward influence (3.5>3.03).
This makes cosmic style far less attractive on a 17 x 17 board. Moreover, it is far easier
for Black to maintain the advantage of playing first, on a smaller board. Thus it was not
surprising that the 17 X 17 board was eventually abolished towards the end of the NanBei Dynasty.