Buckwheat takes exactly twice its volume in liquid and exactly fifteen minutes, then ten more with the lid on and the heat off. Brown the chicken separately and let it finish in the steam rather than boiling in with the grain.
It did not make it into the plan for these seven days.
The method above is what decides the dish, not a step-by-step recipe. The link runs a web search on the name: this page has no vetted sources of its own, and will not invent any.