SAI LOVE JINSEI RUNNER (最愛人生ランナー?) (loosely translated as "Beloved Life Runner") is a promotional track for Sonic Racing: CrossWorlds, released as part of Project ONSOKU, a collection of five new Hatsune Miku songs and music videos made to celebrate her inclusion in the game. The song is written and produced by Kairiki Bear. It debuted alongside its music video on Project ONSOKU’s launch, marking the beginning of a five-week song release schedule.