“he reigned two years over Israel.” The northern kingdom of Israel used a non-accession counting system for their kings in which any part of a year was counted as a year (in contrast to the southern kingdom of Judah, which used an accession-year counting system, in which any part of the first year of a kings reign was not counted because it was counted as part of the final year of the previous king). Ahaziah reigned at least six months in his first year but likely only several months in his “second” year, making his total reign perhaps even less than 12 months, although it could have been a few more months than that.