With Munsell colors j, observers made assessments on the degree of grayness N(j), 0 similar to 10, and the degrees of principal hues xi(alpha)(j) in the chromatic part zeta(j) = 10 - N(j). Based on these data, the optimum directions of principal hue vectors {f(alpha)}, common for colors from 4 similar to 7 V, were determined where alpha means 4 (R, Y, G, B) or 5 (R, Y, G, B, P). Coordinates <(xi)over cap>(alpha) of points (H, V/C) on these vectors and ratios eta(alpha), = xi(alpha)/zeta are called the absolute and relative principal hue components. These values, xi(alpha)(j), zeta(j), and eta(alpha)(j), provide the foundation for denoting a color j by (H-j, V-j/C-j). Curves representing xi(alpha)(H\V, C) or eta(alpha)(H\V, C) as functions of Munsell H with fixed levels of V and C are compared with chromatic response functions on the equal energy spectrum. Of the five Munsell principal hues, Purple was shown not indispensable. The most representative blue was found not at 5B, but close to 5PB in both 4- and 5-Hue assessments. It was discussed how to predict assessments xi(alpha) from <(xi)over cap>(alpha) and zeta from Munsell Chroma, and eta(alpha) by an appropriate combination of <(xi)over cap>(alpha) and zeta