Maestro n° 103 : Page 84 - Gr 81
r5c3 =1= r8c3 -1- r8c9 =1=4= r8c9 -4- r6c9 =4=5= r6c9 -5- r6c3 =5= r5c3 => r5c3 ≠ 4 and r6c7 ≠ 5