For though there were continual skirmishes between Asa and Baasha and their people all their days, 1 Kings 15:16, yet it did not break forth into an open war till Asa's thirty-fifth year, i.e. till that was ended. But how this thirty-fifth year is to be computed, See Poole on "2 Chronicles 16:1".
Related Commentaries of 2 Chronicles 15:19
2 Chronicles 15:19
19 And there was no more war unto the five and thirtieth year of the reign of Asa.