In many places, potato salad is a summer dish. But in Japan it is an all-season food, readily available everywhere from convenience stores to gourmet department store food halls. There's even a specialty potato salad stand in Tokyo’s Jiyugaoka neighborhood called Potato Cream.
Potato salad is a subject I keep coming back to because it is such a personal favorite. My mother made potato salad frequently, of course. And in middle school, on days when my mother was too busy to make me a bento, we would buy something called a "vegetable sandwich." This was basically a shokupan (sliced bread) sandwich filled with potato salad. It was a classic carb-on-carb item, like potato-croquette sandwiches or yakisoba (fried noodles) rolls. In any case, I loved the combination of the soft white bread with the tangy-creamy potato salad. A more “mature” combination I particularly like is grilled Pacific saury (sanma), a quintessential fall fish, served sizzling hot with a dollop of chilled potato salad.
My potato salad recipe has evolved quite a lot over the years (try the 2020 version here), but this is my current favorite. The key to this take is using soup stock in the boiling water, which gives the potatoes a boost of umami while they cook. Just a little sugar is added, too, which enhances the potatoes’ natural sweetness. This, plus the tiny drizzle of soy sauce, makes the potato salad go well with a Japanese-style meal. The cucumber and onion are not sliced super thin in order to keep their crunchy texture. I also like to add tons of black pepper for a spike of spice — sanshō pepper could be used as well.