It's the king of Asian condiments, a 2,500-year-old dark, bitter-salty brew that goes with everything from stir-fry to sushi.
But these days, soy sauce isn't just a culinary flourish -- it's the focus of a global trade dispute.
At a UN-sponsored meeting in Washington scheduled for today, Japan plans to demand new labels on soy sauce bottles that would distinguish traditionally brewed types from newer versions.
The US and others leading the opposition say such rules would penalize some producers, and they want each country to be able to decide for itself. If approved, the proposal could eventually force some brands -- like the US producer ConAgra Foods' La Choy and Chun King -- to disclose that they either take brewing shortcuts or skip the process altogether.
"We think consumers should have a way of telling the difference between traditionally made soy sauce and these other brands that don't even start with soybeans," Japanese Agriculture Ministry official Hironobu Naka said.
Tokyo's campaign, begun in 1998, is the latest front in an escalating war over food. At stake is a slice of a growing market for Asian food, mostly in the US and Europe.
Japan will make its claim today before the Codex Alimentarius Commission's committee on processed fruits and vegetables. The committee will then vote on whether to ask the full commission to debate the proposal next June in Rome.
The Codex commission is obscure, but powerful: It has set international food standards since the 1960s and makes the de facto rules for the WTO's trade-dispute court.
Japan's soy sauce spat mirrors a recent EU battle to push for a global registry that would let certain products, such as Roquefort cheese or Kalamata olives, bear their distinct names only if they come from the original region.
First brewed in China as early as 500BC, soy sauce was brought to Japan a millennium later. Traditionally, it's made from soybeans, salt and grains; Japan's Kikkoman Inc, the world's largest producer of soy sauce, says its own recipe, which dates to the 17th century, requires fermenting for three months or longer.
Newer methods substitute hydrolyzed vegetable or soy proteins -- a type of flavor enhancer -- rather than using the real beans. They also add sugar and bypass brewing or rely on blends.
Industry groups roughly estimate total worldwide consumption at 10 billion liters, with per capita consumption in Japan at about 9 liters a year. US per capita consumption is roughly 0.8 liters and Europe's is even less.
Tokyo initially wanted soy sauce to be strictly defined as a seasoning of brewed soybeans, but has since backed off. It's now calling for labels to say "natural brewing," "short-term brewing" and "mixed."
But Washington and its powerful food lobby are likely to send that proposal back to the kitchen.
The International Hydrolyzed Protein Council says that soy sauce made of hydrolyzed proteins has been on store shelves for decades in the US and other countries.
"The Japanese proposal does not recognize this history of use and would require these products to be marketed under a different name," said Martin Hahn, a partner at law firm Hogan and Hartson in Washington and the council's executive director.
Label rules should reflect "regional difference," and should be decided by import laws in each country, he said.
But consumer groups in the US, Japan and Britain say that without soybeans, it's not soy sauce.
"It would be like saying barbecued beef but without the barbecue," said Bruce Silverglade, legal director of the Center for Science in the Public Interest in Washington.
"Companies making the imitation can call it American-style Oriental sauce, or something else," he said.
Japan's proposal has strong backing from South Korea and some European countries such as France and Switzerland. Others like China don't think it goes far enough, and want to exclude all hydrolyzed protein-made sauces.