Japan — across all regions; kama-meshi (pot rice) in iron pots was the precursor; rice cooker technology democratised takikomi gohan home preparation from the 1950s
Takikomi gohan (mixed rice) is the category of rice dishes in which seasonings and ingredients are cooked together with the rice from the raw state — everything goes into the rice cooker (or pot) simultaneously and steams together, the rice absorbing the flavours of the ingredients and the dashi-seasoned cooking liquid. This is distinct from maze-gohan (mixed-after-cooking) where ingredients are folded into separately cooked rice. Major examples: matsutake gohan (matsutake mushroom rice, peak luxury of autumn), kuri gohan (chestnut rice, autumn), takikomi gohan with burdock and carrot (earthy winter), pea gohan (spring), and saka-mushi steamed clam rice. The rice absorbs the cooking liquid and ingredient essences simultaneously.
The cooking liquid must be seasoned before adding to rice: standard ratio is dashi + 1 tbsp soy + 1 tbsp sake + 1 tsp mirin per 2 cups rice. Liquid volume adjustment: add ingredients after measuring standard water quantity, then reduce water by the volume of liquid the ingredients will release (mushrooms, for example, release significant moisture). Do not stir before cooking — arrange ingredients on top of the raw rice. The lid must not be opened during cooking. Rest 15 minutes after cooking with steam off before folding gently.
The most celebrated takikomi gohan — matsutake gohan — uses only a tiny amount of soy sauce (1 tsp for 2 cups rice) and relies entirely on the extraordinary perfume of the matsutake mushroom to flavour the dish. For maximum matsutake impact: add half the matsutake raw to the rice, add the other half very briefly sautéed in sake and soy as a topping when serving. The residual dashi liquid from other preparations is ideal as the cooking liquid for takikomi gohan. Octopus takikomi gohan (tako gohan) is a beautiful summer variation — the purple octopus tints the rice a faint violet.
Over-seasoning the cooking liquid — the flavours concentrate as liquid reduces and rice absorbs; start lighter than you think necessary. Cutting ingredients too large, which prevents them from cooking evenly within the rice cooking time. Opening the lid to check progress, releasing essential steam that is part of the cooking process. Adding ingredients that require longer cooking than rice (e.g., raw chestnuts without pre-cooking) directly — they will remain undercooked.
Tsuji, Shizuo — Japanese Cooking: A Simple Art; Murata, Yoshihiro — Kaiseki