Definition of 入れ換え戦 (いれかえせん)
いかせん
                        入れ換え戦
いれかえせん
irekaesen
noun
•
        
match-up between wrestlers from different divisions who will probably 'switch' divisions in new ranking(sumo term)
Related Kanji
| 入 | enter, insert | 
| 換 | interchange, period, change, convert, replace, renew | 
| 戦 | war, battle, match |