Definition of 回戦 (かいせん)
かいせん
                        回戦
かいせん
kaisen
Common word
noun (suffix)
1.
event with ... rounds, innings, legs, etc.
2.
nth-round match (in a knockout tournament)
Related Kanji
| 回 | -times, round, game, revolve, counter for occurrences | 
| 戦 | war, battle, match |