Maestro n° 097 : Page 81 - Gr 78
L2C9 -6- L2C2 =6=9= L2C2 -9- L1C3 =9= L8C3 -9-5- L8C3 =5= L8C9 -5-4- L8C9 =4= L2C9 donc L2C9 ≠ 6