An hour outside Tokyo, and we were in Hell, which is a thrilling place to be if you’re only visiting. Owakudani (its less startling name) steams and bubbles with sulphurous hot water so intense that nothing can live there. 

 But it boils eggs really well; the sulphur-blackened eggs are an earnest tradition among the onsen (hot spring)-loving Japanese. “Eat one, gain seven years. Eat two, get fourteen. But eat three, and live till you die,” I was told. 

 A friend ate five but has lived to report the fact that the devil’s food tastes “just like normal boiled eggs”. ¥ 500 for six.