The foreign posting systems are set up to allow foreign players who are already under team control to move to the states and try their hand at Major League Baseball, their original teams would in-turn receive compensation for allowing their players release. If a player, who is posted, fails to come to agreement with a MLB club they stay under contract with their initial club.
The KBO posting period ran from November 10th through December 14th; so all players that would have been eligible to be posted will have done so by now. The last possible negotiation day would then be January 9th for any player posted on the final day of that window (sooner for those players posted earlier in the period).
The NPB posting period ran from November 22nd through December 12th; so all players that would have been eligible to be posted will have done so by now. The last possible negotiation day would then be January 11th for any player posted on the final day of the window (sooner for those players posted earlier in the period).
MLB clubs who sign a player via the KBO or NPB posting system are on the hook to pay a separate release fee to the player's KBO or NPB team, in addition to their newly negotiated contract. The fee is equal to 20 percent of the player's first $25 million in guaranteed salary, 17.5 percent of the next $25 million and 15 percent of any amount beyond $50 million.
22 South Korean-born players have debuted in the major leagues, beginning with Chan Ho Park back in 1994. (doesn't include players that were born in South Korea to American parents or players with Korean ancestry who grew up in the United States)
61 Japanese-born players have debuted in the major leagues, beginning with Masanori Murakami back in 1964. (doesn't include players that were born in Japan to American parents or players with Japanese ancestry who grew up in the United States)
The following players, who played 2020 in the KBO or NPB have been posted this winter:
---31 year old, Korean, Righfielder, Sung-Bum Na
He was posted on December 9th, negotiation window 30 days (agent Scott Boras)
https://www.baseball-reference.com/r...d=na----000sun
---25 year old, Korean, Shortstop, Ha-Seong Kim
He was posted on December 7th, negotiation window 30 days
https://www.baseball-reference.com/r...d=kim---001ha-
---31 year old, Japanese, Right-handed Starting Pitcher, Tomoyuki Sugano
He was posted on December 8th, negotiation window 30 days
https://www.baseball-reference.com/r...d=sugano001tom
---29 year old, Japanese, Rightfielder/SecondBaseman, Haruki Nishikawa
He was posted on December 4th, negotiation window 30 days
https://www.baseball-reference.com/r...d=nishik000har
---28 year old, Japanese, Right-handed Starting Pitcher, Kohei Arihara
He was posted on November 26th, negotiation window 30 days
https://www.baseball-reference.com/r...d=arihar000koh