Japan (nationwide; particular association with nabe hot pot closing and sick-day recovery cooking)
Zosui (雑炊) and ojiya (おじや) are Japan's two overlapping styles of rice porridge — both made by simmering cooked rice in broth until softened, but with distinct traditional connotations and methods. Zosui uses already-cooked (sometimes previously flavoured) rice added to a flavoured broth and simmered briefly — the rice retains some individual grain structure. Ojiya traditionally means a wetter, more broken-down version, simmered longer, where the grains begin to release starch into the broth creating a creamier consistency. Both differ fundamentally from kayu (お粥 okayu) which begins with raw rice and a large amount of water simmered from the start — kayu is Japan's canonical sick-day and recovery food. In practice, the distinction between zosui and ojiya is now largely regional linguistic: both refer to the end-of-nabe (hot pot closing) preparation where remaining broth is used to cook leftover rice into a rich porridge that absorbs all the accumulated flavours of the evening's cooking. The flavoured nabe broth enriched by hours of simmering vegetables, proteins, and dashi becomes the vehicle for an extraordinarily flavoured rice porridge finale. A beaten egg stirred in near the end adds richness and body, finished with sliced negi and nori.
Warm, comforting, savoury-rich broth absorbed into soft rice; complexity from accumulated nabe flavours; egg enrichment adds silkiness; deeply satisfying and restorative
{"Zosui uses pre-cooked rice in flavoured broth — brief simmer retains some grain integrity","Ojiya implies longer cooking and creamier consistency as starch releases","Kayu (okayu) is distinct: made from raw rice with much more water from the start","Nabe shime (hot pot finale): add cooked rice to remaining enriched broth — the ultimate closing preparation","Beaten egg stirred in last 60 seconds of cooking adds richness and silky body"}
{"Miso broth nabe shime: add rice to remaining miso nabe broth; top with additional miso and finish with egg","Sukiyaki zosui: the sweet soy beef broth makes an extraordinary rice porridge — quintessential cold-weather finish","For sick-day okayu: 1 cup rice to 8 cups water, simmer 45 minutes covered; softer than congee but similarly soothing","Ochazuke: pour green tea or dashi over rice in bowl — the instant table-service version of zosui concept"}
{"Adding too much rice to the nabe broth — rice absorbs liquid rapidly; add in small amounts","Over-cooking until completely mushy — zosui should retain some texture; ojiya more creamy but not paste","Not tasting remaining nabe broth before adding rice — highly concentrated broth may need diluting before zosui","Adding cold cooked rice directly — breaks down immediately; bring to room temperature or warm before adding"}
Japanese Farm Food — Nancy Singleton Hachisu; Japanese Cooking: A Simple Art — Shizuo Tsuji