Place the buckwheat groats and 2/3 cup of water in a small saucepan over medium heat, and bring to a boil. Reduce the heat to low, and simmer the buckwheat until the grains have softened, about 10 minutes. Remove from the heat and set aside.
Whisk together the yeast, 1/2 cup of water, and 1/2 cup of bread flour in a bowl, and let stand until the mixture is frothy, about 10 minutes.
In a separate large bowl, stir together the 1/2 cup of water with vegetable oil, honey, salt, whole wheat flour, and anise seed to make a thick, smooth batter. Mix in the yeast mixture and the cooled buckwheat groats. Stir in the remaining 1 1/2 cups of bread flour, 1/2 cup at a time, mixing in each addition before adding the next.
Turn the dough out onto a floured work surface, and knead until the dough is firm, smooth, and elastic, 8 to 10 minutes. Form the dough into a compact ball, and place into an oiled bowl, turning the dough in the bowl to coat with oil. Cover the bowl with a cloth, and let rise in a warm place until doubled in volume, about 1 hour.
Punch down the dough, form into a loaf, and place seam side down into a greased 9x5 inch bread pan. Cover the pan with a cloth, and allow to rise until nearly doubled in volume, about 45 minutes.
Preheat oven to 375 degrees F (190 degrees C).
Bake the bread in the preheated oven until the top is lightly golden brown and the loaf sounds hollow when thumped, about 35 minutes. Allow to cool before slicing.