The media learned yesterday that the NHK's in the 6 prefectures in the Tohoku region will be broadcasting the exhibition game between the Nippon Ham Fighters and Rakuten Eagles on the 27th. While NHK has provided coverage of exhibition games over the radio in the past, there is no evidence that they have ever broadcast exhibition games in the past.
NHK will also be doing a little extra work in order to make the broadcast possible -- NHK Okinawa has a truck that can provide live feeds to other stations across the country, but they're booked (bj League coverage). So for this one game, NHK will be sending equipment down to Okinawa from the Fukuoka offices.
NHK has also already purchased rights to nationally broadcast the Fighters vs Eagles regular game season game on 4/23.