Japan — adapted from Chinese tradition; systematised in 20th century ramen culture
Chashu (Japanese char siu adapted from Chinese cha siu) refers to the slow-braised or slow-roasted pork belly or shoulder that has become the defining topping of Japanese ramen. Unlike Chinese char siu (roasted on hooks with high sugar-caramelised exterior), Japanese chashu is almost always braised/simmered in soy, sake, mirin, and sugar until silky-tender, then often rolled into a cylinder, tied with string, and sliced into rounds for presentation. The braising liquid is reduced to a tare that is itself used to season the ramen broth. Key regional variations: Fukuoka tonkotsu ramen uses very thin-sliced chashu with minimal sauce; Tokyo-style uses thick-cut belly medallions; Sapporo-style uses pork shoulder with more assertive sauce. Contemporary ramen restaurants have elevated chashu to signature dish status — sous-vide chashu at 68°C for 36 hours is the modern benchmark for silky texture.
Sweet-savoury, caramelised soy glaze with silky, melting pork fat; seared surface adds bitter-sweet Maillard notes; braising liquid condenses all flavours into ramen tare
Roll pork belly tightly (or tie shoulder in a uniform cylinder) before braising to create uniform slices; braise in soy/sake/mirin/sugar at gentle simmer (not boil) for 2–3 hours until chopstick-penetrable; cool in the braising liquid for flavour absorption and colour setting; refrigerate before slicing (cold chashu slices cleanly; warm chashu crumbles); sear the sliced rounds on a blowtorch or hot pan before serving to caramelise the surface.
Sous-vide technique: sear rolled pork belly, seal in bag with chashu braising liquid (3 soy: 2 mirin: 1 sake: 1 sugar), cook 68°C for 36 hours — this produces the most texturally consistent, silky chashu without risk of over-cooking; blowtorch finish directly in the bowl before service is the contemporary ramen restaurant standard; chashu is extraordinarily versatile beyond ramen: sliced on top of steamed rice with the cooking liquid, in chashu-don (rice bowl), or in sandwiches (katsu-sando style).
Braising without rolling/tying (produces irregular shapes that don't slice cleanly); boiling instead of gentle simmering (tough, dry exterior with undercooked interior); slicing while hot (disintegrates); discarding braising liquid (it becomes the most umami-rich component of the ramen tare); over-reducing the braising sauce to a sticky jam (it should remain a pourable glaze).
The Japanese Kitchen — Hiroko Shimbo