As I've been detailing before, the Japanese pro leagues (NPB) have a much different playoff setup than those of us across the Really Big Pond.
Since there are just two six-team leagues, the practice for years was just to have the two regular season champs face off in a best of seven series for the big gonfalon. However, the less popular league, the Pacific League, opted to use a playoff system starting in 2004 and the Central League adopted a similar system last year.
The top three teams in each league make the playoffs. Team #2 and #3 play each other in a best of three with all the home games being played at the second place team's home park. The winner then faces the #1 team (who is officially the league champion regardless of the playoff results) in a six-game series where the #1 team needs just three wins while the #2 team must win four. The #1 team also gets to host all the games and they are played over a seven-day span.
The Seibu Lions will host the Hokkaido Nippon Ham Fighters in the second stage of the Pacific League Climax Series starting on Friday. The first game will not be played at Seibu's home stadium, the Seibu Dome, but rather Omiya Stadium Park. The final five (if necessary) will be back in the Seibu Dome. I am guessing that the first game is a sop to the fans in the rest of the Saitama prefecture as the Lions changed their name this year officially to the Saitama Seibu Lions. The Lions home park is actually in Tokorazawa. This map should show you the relative locations of Omiya (with the tag on it) and Tokorazawa which is to the southwest.
In the Central League, the first stage of its Climax Series starts on Saturday with the second place Hanshin Tigers hosting the third place Chunichi Dragons. Those games will not be played at Hanshin's historic Koshien Stadium, which is undergoing renovations, but rather at the Kyocera Dome in Osaka.
The winner of that series would play the Yomiuri Giants starting on October 22 at the Tokyo Dome, which will host all six games.
The Japan Series, matching the winners of both Climax Series, will be start on November 1 at the home of the Central League champ and will be played in a 2-3-2 format.