'Seventh Year' in the Bible

Then Zimri came in and struck and killed Elah in the twenty-seventh year of Asa king of Judah, and became king in his place.

In the twenty-seventh year of Asa king of Judah, Zimri reigned [over Israel] for seven days at Tirzah. Now the troops were camped against Gibbethon, [a city] which belonged to the Philistines,