Buckwheat Noodles Topped with Grated Yam

Prepare the dashi broth: In a small pot, combine water, dashi powder, soy sauce, and mirin. Bring to a gentle simmer over medium heat, then remove from heat. Keep warm.

Prepare the nagaimo: Carefully peel the nagaimo. Using a fine grater, grate the yam into a smooth, slightly sticky paste. Be cautious as nagaimo can cause skin irritation for some; wearing gloves is recommended.

Prepare the garnishes: Thinly slice the green onions. If using nori, cut it into thin strips with kitchen scissors.

Cook the soba noodles: Bring a large pot of water to a rolling boil. Add the soba noodles and cook according to package instructions, typically 3-5 minutes. Drain well.

Assemble the bowls: For hot Tororo Soba, quickly rinse the cooked noodles under hot water to warm them, then drain again. Divide the noodles evenly into two serving bowls.

Serve: Pour the warm dashi broth over the noodles. Top each bowl generously with the grated nagaimo, sliced green onions, and nori strips. Sprinkle with Shichimi Togarashi if desired, and serve immediately.