Mix together the buckwheat and shiratamako, then add water a little at a time until the dough becomes soft (until it becomes, as the Japanese say, "to the softness of an ear lobe").
Boil water in a pot. Form small, round balls from the dough in Step 1, then drop into boiling water. Scoop them out after a minute from the time they rise to the top.
Chill in ice water.
To make the syrup, mix all of the syrup ingredients in a pan. Heat on medium, stirring continuously.
Once it starts to gently boil and thicken, transfer to a dish and let cool to room temperature. Pour on the dumplings, then serve.
They are slightly chewier than dumplings made with just shiratamako and their texture will become addictive.
Story Behind this Recipe
I wanted to make a different type of dumpling than my usual one for moon viewing.
Add the amount of water little by little, depending on how much you need. If the dough is firm, I recommend adding more water. Be sure to continue stirring while making the syrup. If you don't it may form lumps. If too much time passes after boiling them, they may become stiff, so microwave before serving.