Below is the widest path (found by following the most popular response to the most popular move... etc.) for the second half of the 60's as they are represented in GoGoDCD. --DaveSigaty
The path narrows quite quickly in the 65-69 period.
See Shusaku fuseki for more.
The widest path according to MasterGo (enclosure opening):
total: 227 games, black wins 56%
black 1: 167 games, black wins 60%.
white 2: 85 games, black wins 61%.
black 3: 55 games, black wins 60%.
white 4: 14 games, black wins 64%. The two databases diverge here. GoGod's choice (5) occurs 13 times in MasterGo, a occurs 10 times.
black 5: 12 games, black wins 67%.
white 6: 9 games, black wins 72%. Only alternative is the low kakari at 7.
black 7: 9 games, black wins 72%.
white 8: 8 games, black wins 75%. Until black 13 in the next diagram, there is no variation.
White 14: 4 games, black wins 50%. White 18 (3 games) is a close second.
Black 15: 3 games, black wins 33%.
White 16 to white 20: No variation here. After white 20, the widest path ends. Continuations are a, b and c.
The right side pattern has its own page.