Sushi actually means sour-tasting and refers to the vinegared rice, not the raw fish. This episode traces the dish back to Southeast Asia’s Mekong and Irrawaddy river basins, where fish was packed in rice to ferment for months, and follows it through Japan’s shorter namanare fermentation to Edo-era fast sushi made with vinegar.

We cover Hanaya Yohei’s large, hand-pressed nigiri sold from street carts around 1824, the first conveyor belt sushi restaurant in 1958, the disputed origins of the inside-out California roll, and Norway’s 1980s Project Japan campaign that made raw salmon a Japanese favorite. We also explain imitation wasabi, why raw fish is flash-frozen, and why you should dip the fish side of nigiri, not the rice, in soy sauce.

• Why narezushi, fish fermented in rice, is the earliest ancestor of sushi
• How vinegar replaced fermentation in Edo and led to Hanaya Yohei’s nigiri
• How the conveyor belt and the inside-out California roll made sushi more approachable
• How Norway’s farmed, parasite-free Atlantic salmon overcame Japan’s aversion to eating salmon raw
• The truth about green wasabi paste, flash-freezing for safety, and proper nigiri etiquette