Asahikawa City, Hokkaido, Japan. Ramen arrived from Chinese influences in the early 20th century; the W-soup technique is credited to Asahikawa's pioneering ramen shop Hachiya (蜂屋), operating since 1947.
Asahikawa ramen, from Hokkaido's second city, is defined by its W-soup (ダブルスープ) system — a technique unique to this style where two separate broths are made (typically pork bone and dried seafood/fish) and combined at service to create a layered complexity that neither provides alone. The result is a broth of unusual depth: the pork bone provides body and richness, the seafood (niboshi sardines, ago flying fish) provides umami and a slightly bitter oceanic note. Combined with a soy tare, the Asahikawa bowl is dark amber and intensely savoury. Asahikawa is colder than Sapporo for much of the winter — the ramen is accordingly more warming and rich.
Asahikawa's W-soup ramen delivers a complex, dark, intensely savoury broth with a slightly bitter-oceanic edge from the dried seafood (niboshi) layered over the pork bone's richness. The combination is neither fully fishy nor fully porky — it exists in a flavour space neither stock alone can reach. The soy tare adds depth and colour. The fat layer on the surface gradually melts into each spoonful, adding richness. This is ramen designed for cold — warming, dense, layered.
The W-soup technique: broth A (pork bone or chicken, simmered for 6–8 hours) and broth B (dried seafood — niboshi, katsuobushi, kombu — cold-extracted or briefly simmered) are kept separate until service. At service, specific ratios of each are combined in the bowl before adding tare. The combination ratio varies by shop — some use 60:40, others 70:30. The balance point creates a synergistic umami from the pork bone's inosinate and the seafood's glutamate/inosinate combining with the tare's fermented soy depth. A thin film of pork or chicken fat floats on the surface — essential for keeping the bowl hot in Asahikawa's cold winters.
The W-soup technique, while local to Asahikawa, represents a broader principle applicable to any ramen kitchen: keeping base stocks separated and combining at service preserves each stock's character and allows the combination to be adjusted per dish. Some Asahikawa shops have three stocks (pork, chicken, seafood) and combine them in varying ratios. The cold weather context explains the fat layer tradition — a floating oil layer insulates the broth surface and keeps the bowl hot significantly longer than a fat-free broth.
Combining the stocks in the pot rather than per-bowl at service — the two stocks should remain separate until service for maximum freshness of each. Incorrect combination ratio — the W-soup balance is shop-specific and arrived at through iteration, not formula. Inadequate niboshi sourcing — the dried sardine character is essential and varies dramatically with quality.
Ramen documentation; Hokkaido culinary tradition