In 1975, a kabuki actor who had been named a Living National Treasure ate four portions of banned pufferfish liver in Kyoto and died hours later. This episode explains why fugu is so dangerous and why people eat it anyway. Tetrodotoxin blocks sodium channels in the nerves, which paralyzes the body while the victim stays conscious, and there is no antidote. The pufferfish does not make the toxin itself. It builds up from marine bacteria through the food chain, and mutations in its own sodium channels keep it safe.

We cover fugu bones found in Jomon-period shell mounds, the Tokugawa bans, Su Shi’s praise of its flavor, and Captain Cook’s near-poisoning in 1774. Then we look at Japan’s licensing system, where only about 35 percent pass on the first try, and South Korea’s timed 56-minute practical exam. We also cover the black market for fugu liver, Ishikawa’s ovaries pickled for three years until the toxin breaks down, and farmed fugu raised without the toxin, which China legalized in 2016.

• How tetrodotoxin shuts down nerve signals
• Why pufferfish are immune to their own poison
• The paper-thin usuzukuri sashimi and the dedicated fugu hiki knife
• Why most poisonings happen in home kitchens and through fraud
• Whether toxin-free farmed fugu takes away the danger that made it famous