Make the dashi by diluting the shiro-dashi with boiling water (hot green tea with a pinch of salt also works).
Put rice in a bowl and top with the potato chips, lightly broken by hand.
Scatter shredded nori, green onion and white sesame, and add wasabi if you like.
Pour the dashi over just before eating.
Right after pouring, the chips on top are crisp; leave them a moment and they soak up the dashi and soften, spreading potato-and-dashi umami. Enjoy both textures. ConsommE or nori-salt flavors also work, and a little black pepper or a knob of butter makes it Western-style.