## NZ Herald Hard Fri 9 Sep 2005 - needs trial & error?

All about puzzles in newspapers, magazines, and books

### NZ Herald Hard Fri 9 Sep 2005 - needs trial & error?

A friend and I have independently worked on this, eschewing trial and error. We each get as far as 46 numbers and then are stuck. Trial and error easily solves the puzzle from there but I understood that it is not supposed to be necessary.

I have got to:

**76*82*1
*652**3*8
2*8*4**6*
721*368*4
85342****
64981**32
*76*8*425
5*2**49**
9*4**2***

and have enumerated the possibilities for each remaining cell.

retep

Posts: 2
Joined: 10 September 2005

There is a swordfish in 5's in cells:

(r1c5)(r1c8)(r4c4)(r4c8)(r9c4)(r9c5)

This enables you to eliminate the 5 in cell (r6c7) leaving a 7 to be placed.
MCC

Posts: 1275
Joined: 08 June 2005

Ignore the above, although there is a swordfish, the 5 in (r6c7) cannot be eliminated.
But the 5 in (r3c4) can be eliminated because either (r4c4) or (r9c4) must be a 5.
Not really sure that it helps move the puzzle on.
MCC

Posts: 1275
Joined: 08 June 2005

### re: NZ Herald 2005.Sep.9

.

retep wrote:I have got to 46:

Code: Select all
` . . 7 | 6 . 8 | 2 . 1  . 6 5 | 2 . . | 3 . 8  2 . 8 | . 4 . | . 6 . -------+-------+------ 7 2 1 | . 3 6 | 8 . 4  8 5 3 | 4 2 . | . . .  6 4 9 | 8 1 . | . 3 2 -------+-------+------ . 7 6 | . 8 . | 4 2 5  5 . 2 | . . 4 | 9 . .  9 . 4 | . . 2 | . . . `

• box Middle-Middle needs a 7, which can only go in c6; eliminate 7 elsewhere in c6
• c5 needs a 9, which can only go in box Top-Middle; eliminate 9 elsewhere in TM
thus the list of possibilities for r2c6 is reduced from { 1,7,9 } to just { 1 }

.

Pat

Posts: 3710
Joined: 18 July 2005

Pat - many thanks for pointing this out so simply and clearly.
Now it looks obvious!
retep

Posts: 2
Joined: 10 September 2005