The financial strength (A+/Positive) and issuer credit (A+/Positive/--) ratings on Japan-based Aflac Life Insurance Japan Ltd. (Aflac Japan) reflect S&P Global Ratings' view that the insurer is a core subsidiary of U.S.-based insurance group, Aflac. Our ratings on the core subsidiaries of the Aflac group are constrained by our ratings on Japan (A+/Positive/A-1) because the majority of the Aflac group's assets and earnings are from Japan. Aflac Japan was converted into a Japanese subsidiary from a branch of the Aflac group on April 2, 2018. We view the insurer as a core subsidiary of the Aflac group because the Japanese operations comprise approximately 75% of the group's operating earnings and are the primary generator of its revenue and cash flow.