## Fridays killer and tip

For fans of Killer Sudoku, Samurai Sudoku and other variants

### Fridays killer and tip

12 mins my a***. (well for me anyway!) took about 45 mins but i finally got it.

Got a useful hint if noone has thought of it yet.

if you take rows eight and nine the total must be 90. which means r7,c1 and r7,c9 must add up to 6. given i had other numbers i was able to pinpoint which two numbers they should be. Similarly this works for rows one and two.

i hope i am not being too obvious but i thought it might help some of us who are still getting to grips with this great new version.

domt

Posts: 16
Joined: 01 September 2005

Yes, people have mentioned this trick in the context of doing it with just one block of 45, but certainly it extends to more. I believe in the Deadly on Wednesday, you could fill a couple of cells by using a "135-trick", where a cingle cell in an enclosure stuck out from the entire left block (also the right block as it was symmetrical).

Here it is. You can place r3c4 because the eight leftmost enclosures cover the entire left block (which must total 135) and that extra square. So the eight enclosures' total less 135 gives the number for that cell (same logic for r7c6.
PaulIQ164

Posts: 533
Joined: 16 July 2005

Using the box total =45 logic, the 26 enclosure lapping the top right hand and middle right hand boxes is split horizontally 12 + 14. If we know that numbers within an enclosure must be unique then this helps fill the box. If numbers within an enclosure can repeat if they are in different boxes then this 26 enclosure could be r3c8=5, r3c9=7 with r4c8=9 and r4c9=5 for example. This is why we need clarification on whether repeats are allowed within an enclosure ASAP.
silvercar

Posts: 24
Joined: 05 July 2005

Yes. Though that puzzle is solveable without assuming that The Controversial Rule holds, it would me nice to be told by The Times themselves whether or not it is a rule, so it doesn't feel like cheating using it.
PaulIQ164

Posts: 533
Joined: 16 July 2005

### Fridays killer

Does anyone have a digital image of friday's killer su doku, i am stuck in babysitting and dont have a copy, any help in making my evening go faster are appreciated

ty
zaphod

Posts: 7
Joined: 01 September 2005