Ichiran Shibuya ★ 4.0
Ichiran in Tokyo's Shibuya runs 24-hour tonkotsu ramen for solo-booth eaters. The vending-machine ticket and slip make it the canonical late bowl.
Try: Tonkotsu ramen with custom slip
Tip: Quietest 02:00 to 06:00; busiest 22:00 to 02:00 on weekends.