This was the second version of the portrait of the woman, J.C. of Boetzelaer. He has painted her at least 4 times, twice in profile. What you see clearly in these portraits is his great admiration for the Italian Piero della Francesca, the master of the early Italian Renaissance. Compare the portraits of The Duke and Duchess of Urbino, with this portrait. You can clearly see similarities with this portrait. Before the war, Koch often traveled with his wife to Italy. For a while, they even had a bed-and-breakfast near Florence, where Koch found much inspiration. (http://www.kunstdwalingen.nl/tag/pyke-koch/)