Peel chestnuts

1. Bring a pot of water to a boil, add chestnuts and soak for 10 minutes.
2. Peel off the outer hard skin, leaving the astringent skin (soft skin inside). Peel the lower hard part first, and then peel the upper part by tearing it. Peel slowly and carefully so as not to damage the astringent skin.

Boil chestnuts

1. Boil water in a pot and add 2 teaspoons of baking soda.
2. Bring to a boil, add chestnuts, reduce heat to medium and simmer for 10 minutes. You do not need to remove the stock because it will be boiled off.
3. Transfer the chestnuts, still in the pot, to a colander and drain off the water. Immediately prepare clean water in the pot and bring it to a boil. Once it reaches a boil, boil the chestnuts again for about 10 minutes, then drain off the water.
4. Repeat the blanching process 4-5 times. Initially, the boiling liquid may appear dark, but continue the blanching process until the liquid becomes transparent and slightly reddish in color.

Cleaning chestnuts

1. Using a bamboo skewer or your fingers, remove any black fibers or strands attached to the astringent skin. (Some of the black fibers are difficult to remove, so do not rub too hard as this may cause the astringent skin to tear. Leave the hard-to-remove parts as they are.)
2. After removing the black fibers, you will notice a light brown color with a woodgrain-like pattern throughout the chestnut.

Weigh the chestnuts and prepare the sugar

1. Once you have finished cleaning the astringent skins, weigh all the chestnuts and prepare 60 percent of the total weight in granulated sugar.

Add sugar and boil chestnuts

1. Put the chestnuts in a pot and add enough water to cover them, along with half of the granulated sugar. Place the pot over heat.
2. Bring to a boil and when all the sugar added at the beginning has dissolved, add the remaining sugar. Remove the scum, cover with a paper drop-lid, and boil for 20 minutes over low heat, just enough to release fine bubbles.
3. Turn off the heat and let the pot cool with the chestnuts in it. If the syrup seems too thin, avoid continuing to cook it directly with the chestnuts as it may cause them to lose their shape. Instead, take out a portion of the syrup and simmer it separately in another pot to reduce it. Once reduced, combine it with the original syrup.
4. After it has cooled, you can optionally add brandy or other liqueurs for extra flavor. It can be enjoyed immediately, but the flavor will further penetrate the chestnuts and improve if you let them sit for a day or longer.