Summer 2001 I got the GoGoD Database CD ROM from John Fairbairn and T. Mark Hall. There are nearly 12,000 games in the database. With the tools that John wrote, I gathered some statistics about Cho's opening play. At the time I did this, there were 1154 games by Cho in the database (and in mine, I send John the Cho games I have found). I compared them with all the games from 1966 and later. I didn't differentiate for the different komi (note that there are some 80 Oteai non komi games by Cho).
O P E N I N G
P A T T E R N
|Cho with Black||Cho with White||Database games (from 1966)|
|% win||N||% win||N||% B win||N|
|Any pattern (all games)||63.5%||575||59.6%||579||53.2%||8196|
|Opening with Hoshi||60.8%||319||58.9%||360||53.7%||5368|
|Ni ren sei (including san ren sei)||57.1%||107||59.3%||113||54,5%||1469|
|San ren sei||51.4%||37||69.1%||55||50.1%||437|
|Opening with Komoku||68.7%||217||61.0%||210||52.4%||2560|
|Any low shimari (first five moves)||65.2%||141||58,9%||175||51.9%||1785|
|Low shimari + komoku parallel||63.5%||52||58.3%||36||54.3%||488|
|Low shimari + hoshi parallel||53.8%||13||54.3%||46||50.5%||479|
|Low shimari + sansan parallel||83.3%||6||50.0%||2||51.0%||49|
|Variant 1-3-5 (5 on Hoshi)||90.9%||11||None||0||60.0%||70|
|Opening with sansan||58.6%||29||100%||5||50.5%||105|
|Sansan on move 1 or 3 (or both)||61.8%||34||86.7%||14||-//-||-//-|
Percentages and counts include rotations and mirror images of the (standard) opening pattern. I think these figures are quite interesting, but please draw your own conclusions.
Where does Cho play the second move with white?
A couple of years ago I already noticed that Cho plays his second move more often in the adjacent corner than in the diagonally opposite corner. Thanks again to the database I could now actually count this, and compare it to the overall pattern. The results are really surprising. Against hoshi Cho has played 76% in the adjacent corner, the over-all average is 56.4%. Against komoku Cho has played 83.3% of his second move in the adjacent corner, the over-all average is 67.4%.
Now what does that mean? It probably means that stronger players would welcome a diagonal fuseki, which might be a little bit too slow for black with 5.5 komi. As an example, take all the games in the database [from 1966], where black plays a low chinese fuseki and white opposes with two hoshi's. White wins exactly 50% (of 102 games) when he plays the second move in the adjacent corner, and only 45.7% (of 116 games) when move 2 is in the diagonally opposite corner. There is only one possible conclusion: the players that played in the adjacent corner were the stronger players!