A unate function can easily be identified on a Karnaugh map from the well-known property that it consists only of essential prime implicants which intersect at a common implicant. The additional property that the plot of a unate functionF(x1⃛xn) on a Karnaugh map should possess in order thatFmay also be 1-realizable (n≤6) has been found. It has been shown that the 1-realizability of a unate functionFcorresponds to the ‘ compactness ’ of the plot ofF. No resort to the inequalities is made, and no pre-processing such as positivizing and ordering of the given function is required.