Egg prices are surging in Japan largely because the cost of feeding hens is too. Russia's invasion of Ukraine sent those prices rocketing, and the spread of bird flu in the country has made matters worse.

A subsidiary of the National Federation of Agricultural Cooperative Associations says the average wholesale price of medium-sized eggs in Tokyo was 262 yen, or about 1.9 dollars per kilogram in November.

That's up 26.5 percent from a year earlier and is the highest on record for that month.

Eggs aren't usually as susceptible to price swings as some food items in Japan. They are so important to the food industry that manufacturers have built-in a high degree of efficiency that usually absorbs any external price pressures.