Remove the seeds from the kabocha and cut into 1½-inch (4 cm) cubes. Cut off the hard edges and corners of the pieces, if you want them rounder and smooth.
In a medium saucepan, bring the dashi to a boil. Add the kabocha. Cover and cook over medium heat until the kabocha is tender, 10 to 15 minutes.
Add the sugar, soy sauce, sake, and salt. Reduce the