Like gin and tonic without the lime, like Hendrix without the guitar, sushi wouldn't be sushi without Japanese soy sauce.
You might pay scant attention to that funny bottle with the bright red cap, but for many, soy sauce is serious business, worthy even of a pilgrimage to its homeland of Yuasa.
A 40-minute train ride from Wakayama City (about 100 kilometers south of Osaka), the tiny town of Yuasa is the birthplace of the fermented condiment.
It also happens to be a great place to revisit Japan's historic Edo period (1603-1868).
Here's how the salty legend goes
Some 750 years ago, a Japanese priest arrived in Yuasa after a trip to China, bringing with him a newfound skill for making miso (soybean paste). Soy sauce was discovered accidentally -- a byproduct of the miso-making process.
Yuasa soon became the country's most important soy sauce brewing center.
Despite being a town of just a thousand or so houses, at one time it was crammed with more than 90 soy sauce stores, almost one soy sauce shop for every 10 homes.
Today, the entire city is protected by Japanese law -- its of 323 houses and other traditional buildings (four soy sauce breweries included) recognized for their immense cultural value.
Called "hongawara," some of the oldest buildings date back more than 400 years. Many still have their traditional lattice windows and curved tile roofs.
Generally tranquil, Yuasa is the kind of place where friendly residents chitchat with neighbors and museums and shops are often left open and unattended.
Travelers can sign out free bikes or check out the historic area on foot. In addition to the old soy sauce breweries, there are shrines and other interesting pieces of architecture worth some Facebook bragging.
The Yuasa area is stocked with historic attractions.
Founded in 1841, Kadocho is one of the area's oldest soy sauce factories. It still uses the same huge tub it always has to brew soy sauce. It also has an exhibition hall across the street with the original tools used to brew soy sauce.
During Yuasa's annual Andon (paper lantern) Festival, the streets of town are lighted with paper lanterns; the Andon Gallery is an ode to the Japanese paper lantern.
Formerly a public bathhouse dating to the Edo period, Jinburo has displays documenting life in ancient Yuasa.
Renovated cafes in Edo-period machiya (traditional wooden houses) and a 113-year-old sushi restaurant, Nihonryori Yokogusu, offer visitors a way to check out the interiors of Yuasa's old structures.
Getting there and around
To get to Yuasa, take the JR Line to Yuasa station, 40 minutes from Wakayama City Station and 80 minutes from Osaka's Kansai Airport.
Yuasa's main pedestrian zone is about a 15-minute walk from Yuasa JR station or five minutes by bike.
Free loaner bikes and maps can be found at the information center across from the Yuasa train station, behind the taxi stop.
Some museums and shops are closed on Sunday.
Yuasa Information Center, 1077-6 Yuasa, Yuasa-cho; +81 0737 63 4123; open daily, except December 29-January 3; 9 a.m.-5 p.m.