序盤 Joban is the Japanese term for the beginning phase of the game. Typically the opening involves dividing up the board in a fuseki. However, occasionally in games fighting begins immediately in one corner and spills out across the board.
There is one example of a Joban without a fuseki at single-minded large avalanche. Here is another.
1928-03-21: Kitani Minoru - Hashimoto Utaro
6 at S14
The action in the lower right finally ends when Black extends with . White preempts the bottom left with
. But does Black turn away to the empty corner at the top? Of course not! Instead he digs right in with 6 and the two of them go at it again. But this is running to too many diagrams, so...
I will simply add that the board looks like this 45 moves later when White finally turns to the last open corner. --DaveSigaty