My colleague Boris gave me a jar of horseradish mayonnaise imported from Russia. Having enjoyed it on roast beef sandwiches, and even ham sandwiches, I decided to do a comparison with the Japanese equivalent, purchased at Kotobukiya in the Porter Exchange (a.k.a. “Little Tokyo”) in Cambridge. Japan won the real Russo-Japanese War, which may explain why their mayo is definitely hotter than the Russian variety — too hot for sandwiches, in fact. It’s fine in small quantities on appropriate varieties of sushi, but it needs to be diluted 50-50 with regular mayo when used on sandwiches. Russian wins for that purpose, since it can be used as is. I just thought you ought to know.