grandmaitre n° 17 : Page 51 - Grille 38
L4C8 -7- L4C1 =7=1= L4C1 -1- L4C4 =1= L9C4 -1- L9C5 =1=7= L9C5 -7- L7C5 =7= L7C8 -7- L4C8 donc L4C8 ≠ 7