Takeya Nakamura (SEI) hit a grand slam in the first inning against the Rakuten Eagles last night. His last three home runs are now all grand slams, a new NPB record. On a side note, 34 players (including Nakamura) have hit at least 3 grand slams in a season 36 times in NPB history (but only Nakamura has done it consecutively).
Nakamura also recorded his 10th grand slam of his career in his 9th season. That's faster than Norihiro Nakamura and Alex Ramirez (they both hit their 10th grand slam in their 10th season).