Immerse 1 packet of Kyoto Limited Edition: Kayanoya Dashi Stock Powder with Tuna and Kelp in water in a small pot, bring to a boil, then simmer on medium heat for 2--3 minutes. Add tofu on low heat till warm.
In another small pot, combine Kayanoya Double-Aging Soy Sauce, mirin, sake, and contents of dashi packet. Bring to a boil, then simmer on low heat for 1--2 minutes.
Once tofu has warmed, use any strainer utensil to place pieces in small bowls, then spoon on dashi sauce (#3). Garnish with green onions and bonito flakes.