• Gather all the ingredients.
  

To Make the Dashi

• In a small saucepan, boil 1¾ cups water for the dashi. Once boiling, add ½ cup katsuobushi (dried bonito flakes).
  
• Stir and turn off the heat. Set aside for 15 minutes to steep. Then, strain out the katsuobushi with a fine-mesh sieve. Now you have Katsuo Dashi. Set it aside. Tip: Reserve the spent katsuobushi to make furikake (rice seasonings).
  

To Cut the Kabocha

• Scoop out the seeds and membrane from 1 lb kabocha squash. Microwave it for 2 minutes to soften the outer skin. You can skip microwaving if you have a sharp knife and the strength to cut through the hard kabocha. Tip: See my tutorial and video on How to Cut a Kabocha Squash for more detailed instructions and techniques.
  
• Carefully cut the kabocha into wedges, then 2-inch (5 cm) pieces. Remember, we leave the skin on because it is edible and nutritious.
  

To Cook

• Place the kabocha pieces in a single layer, skin side down, in a large pot.
  
• Add the dashi, 2 Tbsp sake, and 1 Tbsp sugar. Swirl the pot to mix the seasonings so you don‘t break the kabocha pieces by stirring.
  
• Turn on the stove to medium high and bring it to a boil.
  
• Add 2 tsp soy sauce and ⅛ tsp Diamond Crystal kosher salt, and swirl the pot again to mix the seasonings. The cooking liquid should come three-quarters up the sides of the kabocha pieces; if it does not, you can add a little water. Bring it to a boil again.
  
• Once boiling, reduce the heat to medium low and maintain a simmer. Place an otoshibuta (drop lid) directly on the kabocha; learn how to make it at home or find it on Amazon and JOC Goods.

  Cook for 20–30 minutes, depending on the size of the pieces and skin thickness. It‘s done cooking when the orange flesh has tiny, thin cracks near the skin or a bamboo skewer pierces the flesh easily. If the liquid evaporates too fast, you can cover the pot with the pot lid (with the otoshibuta still in place).
  
• Remove from the heat. Cover with the pot lid and let sit until cool, about 30 minutes. This helps the kabocha absorb more flavor.

To Serve

• You can serve the simmered kabocha at room temperature or reheat before serving. To garnish with ginger (optional), cut it into thin slices and then thin julienne strips.
  
• Soak in cold water for 1 minute to remove some of the spiciness. Drain well. Sprinkle the ginger on top of the kabocha.
  

To Store

• You can keep the leftovers in an airtight container and store in the refrigerator for 2–3 days or in the freezer for a month.