As we know the Haru Koshien (i.e. Spring Koshien, Senbatsu) is an invitational tournament.
The question is, how are the invitations handed out?
Well, they are given out based upon the results of the fall tournament. But unlike the Natsu Koshien, each prefecture doesn't get a bid. Instead, regions get bids. Mandatory bids are as follows:
- Hokkaido - 1
- Tohoku - 2
- Kanto (ex Tokyo) - 4
- Tokyo - 1
- Hokushinetsu - 2
- Tokai - 2
- Kinki - 6
- Chuugoku - 2
- Shikoku - 2
- Kyushu - 4
21st century teams are a way to give teams who may get close to qualifying a chance to compete. A team from each prefecture is nominated around November-December. Then each region nominates one of those nominees to the selection committee by December 15th. Finally, the committee selects the three 21st century teams.
There is one catch. The 21st century team cannot be from a region that has received a "flex" bid. Therefore, 6 of the 10 regions will receive an extra bid.
So that's the high level summary. Let's delve down further.
Well, each region has their own tournament. And in general they take the top finishers from each prefecture and put them in semi-seeded brackets to determine the winner. Some prefectures will get more bids in the regionals than others.
Within each prefecture their qualifiers can vary. Most at the top have a traditional single elimination bracket. But to get to that bracket, some have area round-robin play with winners advancing to the next level. Others give bids to the prefectural brackets via a double, or even triple elimination depending on how many that particular area gets.
So unlike the Natsu Koshien qualifying, losing doesn't always mean you're automatically eliminated.
But because the formats all vary, I may not be able to provide as detailed information as I'd like.
There you have it. And because some regions started fall tournaments while Natsu Koshien was still running, the baseball season literally doesn't stop. You finish the Natsu Koshien qualifying, then turn around and get the new team together and ready for the fall tournament. No wonder why seeing 1st years is rare.