Baseball has a long history in Japan. Their fans are extremely loud and boisterous at games. Teams take great pride in fielding competitive squads. There is honor bound within the tradition of Japanese baseball.
There are limits on the number of foreign players on any team roster. And there is a bias against foreign players setting Japanese baseball records. The league is smaller than U.S. MLB. The talent level used to be considered much weaker than the United States, but Japan has done very well in the last several World Baseball events to raise some interest.
Since Japan has a long history of professional baseball, Japanese players could not hit the free agent market like American players. Japanese players are tied to their clubs for a maximum of 9 years. In the United States, there are various CBA provisions that allow more player movement, such as minor league free agency, Rule 5 draft, 40 man protective roster, arbitration for eligible players before free agency, etc.
Under the old system, a Japanese team could "post" or offer a U.S. team the opportunity to negotiate a contract with one of their players. The posting fee would be paid to the team holding the player contract (though some reports state there may be a contractual split of the posting fee). Only one team could "win" the posting bid, and thus awarded exclusive negotiating rights to a star player. The team would give up its star players for two reasons: a) money to be financially viable or profitable and b) pressure from the players themselves to allow them to reach the majors and/or be paid highly for their services.
The posting fees have gotten extremely large in recent years, with the Rangers allegedly paying $51.5 million just for the privilege of signing RHP pitcher Darvish for even a greater sum. The concept of $100 million plus outlays of cash for Japanese players, even the very best ones, seemed to be an runaway train for U.S. clubs. Only the big market, big money teams could afford to spend that kind of money on Japanese players. Small market teams were not big players due to financial restraints.
The posting system is supposed to change. The significant change is that now a Japanese team will set the posting fee for its players, up to a maximum of $20 million. In the past, MLB teams set the posting fee amount. For secondary players, the posting fee could have been much lower than the Darvish sweepstakes. So a small market team could bid $1 million post fee for a secondary player and win the rights to sign him; but now the Japanese club can set the same player post value much higher. In theory, the Japanese club will set the fee market. So, Japanese teams believe they will receive more overall posting fee revenue as a result of the change.
It puts more team into play for talent. If more than one team bids the new posting fee, all those teams can negotiate with the player. The player is rewarded with actual free market competition for his services, which means a larger contract. It probably will result in more good will for the player's former team if and when he returns to Japan at the end of his career.
So the change in the posting system is supposed to rise all boats in the free agent sea.
Final details are still to be worked out between league officials. But there is one thing that will not change: a Japanese club may decide not to post its star player. This may happen with this year's star player, pitcher Tanaka. His team wanted Darvish posting fee money, but with the cap, it will not receive it. So they can keep Tanaka under contract until he reaches his league free agency term.