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Source to write down solution for tough 09/19: Sudoku 09/19.

From easy elimination we get:

459_8__3__27__1___79__256_45__46

159_6__59_3___29__4___125_8___7

14__2__7__8___5___6___13__134_9

459_34_6__47__39__179_8___157_2

2___7__1__5___6___8___4___9___3

8___34_59_247_239_179_156_157_16

3___9__2__1___4___5___7___6___8

6___5__8__9___7___2___13__134_14

7___1__4__6___8___3___9___2___5

here 1 and 3 fill g2 and g7 so g8<>1%c and a8=1%r. Now

59__8___3___27__1___79__256_45__46

1___6___59__3___29__4___25__8___7

4___2___7___8___5___6___13__13__9

59__34__6___47__39__179_8___157_2

2___7___1___5___6___8___4___9___3

8___34__59__247_239_179_156_157_16

3___9___2___1___4___5___7___6___8

6___5___8___9___7___2___13__134_14

7___1___4___6___8___3___9___2___5

wether a9=5 or 9, e6=3 (if a9=5,a6=9%,e6=3% and if a9=9,e8=9%b,e6=3). From here, all is simple elimination (if needed: b4=3~block,b6=4~block,d4=4~block,e4=2~block,d9=2~block,f9=7~block,e8=9~block,a9=9~block,c4=9~block,f6=9~block,d6=7~block,h4=7~block,c8=5~block,a6=5~block,g4=5~block,i4=6~block,g9=6~block,h9=5~block,i9=4~block,h2=4~block,g2=3~block,h7=3~block,g8=2~block,g7=1~block,h6=1~block,f4=1~block,i2=1~block).