In order to draft the basic jacket sloper, the following measurements are needed: 1/2 = chest circumference + 3-1/2” for ease, center front to center back 1/2 = front chest. 1/2 shoulder blade SEE SIZE CHART 1= back neck point 1 to 2 = back waist length (center back) 2 = waist 3 = 1/2 of 1 to 2 4 = chest 3 To 4 = 1- ¾” 1 to 5 = 1/5 of 1 to 4 5 = shoulder guideline Square off from 1, 5, 4, and 2 toward left 4 to 6 = 1/2 front chest + 3-1/2” for ease 6 to 7 = 1/2 front chest + 3/8” 8 = 1/2 of 6 to 7 4 to 9 = 1/2 shoulder blade less ¼” 10 = 1/2 of 9 to 7 to establish side seam Square up and down from 6 to establish center front Square up and down from 8, 7, and 9 Square down from 10 to waist 11 to 12 = 11 to 13 less ¾” Square off 12 to 14 14 to 15 = ¾” Connect 12 to 15 with straight lineIn order to draft neck and shoulder lines, the following measurement is needed: Shoulder length SEE SIZE CHART Back 1 to A = 11 to 13 less 5/8” A to B = back neck rise = 1/3” of 1 to A less ¼” C = 1/2 A to B C to D = shoulder length less 1/8” Connect C to D with straight line as a guide E = 1/2 C to D Connect B to E with hip curve ruler, joining E to D to finish back shoulder 1 to F = 1/8” Connect B to F with sleigh curve ruler to finish back neckline Front 13 to G = B to D less 3/8” to establish front shoulder length Connect 13 to G with straight line H = 1/3 of 15 to 12 Connect 13 to H with sleigh curve ruler Connect H to 12 with straight line to finish nick line for jacket sloperFront armhole Preparation: 1 = lower 1/3 16 to 17 Connect 1 to 10: then connect 1 to G To locate J square off along the line between 1 and 10 to 7 K = 1/2 of J to 7 L = 1” from 10 M = 1/2 of G to 1 M to N = ¼” Back armhole Preparation: O = 1/2 of 17 to 9 Connect O to 10 To locate P, square off along line between O and 10 to 9 P to Q = 1/3 of P to 9Completion of armhole Connect G to N to I with sleigh curve ruler Connect I to K to L to 10 to finish front armhole Connect O to Q to 10; then O to D with shallow part of sleigh curve ruler to finish Back armholeA to B = jacket length C is at waistline Square off from D to H, E to I, F to J, and G to K. C to L = 8” G to M = 8” Connect L to M to finish hip line Connect B to K to finish hemline

{Credit}Masaaki Kawashima’s Buy this book from Amazon

Fundamentals of Men’s Fashion Design: A Guide to Tailored Clothes