For those not familiar with Shogi, it is similar to chess, with an element of Bughouse thrown in. Pieces that you capture actually become part of your army, and can be dropped on the board (subject to restrictions) in place of moving a piece. This makes the game more complex than chess, at least in terms of search space, as a program has to not only generate moves but also examine 'drops'.
One of the interesting aspects of this match is that it actually took place at all. Previously the Japanese Shogi Federation has stopped human v computer matches involving its members, threatening players with sanctions of they play such a match without permission.
There are a number of stories on the web about this match, including this one.