Complex sentence: The ICU promotes Chess in Ireland, maintains the chess rating for players in Ireland which are published three times a year and runs competitions such as the Irish Chess Championship, and selects teams to participate in International Competitions for Ireland.
Split into simpler sentences: The ICU promotes Chess in Ireland and maintains the chess rating for players in Ireland, which are published three times a year. It runs competitions such as the Irish Chess Championship and selects teams to participate in international competitions for Ireland.