This is diagonally symmetrical, so the bottom left reflects in the top right.

The 5's in r24 and c2 meet to form a L. This is also the same for the 6's in r22 and c4, then the same for the 7's in r19 and c7, and finally the same for the 9's in r15 and c11.

Then from either end of the 'L' shape go across two squares each time in a diagonal pattern until you reach the side. So for example, for the 'L' shape made from the two 6's, the diagonal pattern would be r17/C3-4, r16/c2-3, r15/c1-2, r14/c1 and then r23/c9-10, r24/c10-11, r25/c11-12.

I hope this helps, let me know if you need anymore help.

Thanks Puzzledanita.

Thanks Puzzledanita couldn't have done it without you help.

Ye thx.

Thanks for the help, and thanks for the Hanji.

Thanks, the hints helped me to save a lot of time.

Thank you for the tips!

Thanks.