## Moderate puzzle for a beginner...

Post the puzzle or solving technique that's causing you trouble and someone will help

### Moderate puzzle for a beginner...

It began as:

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

and has come to:

Code: Select all
`23  347 247 | 5 1 8 | 6  9   47168 16  5   | 7 9 4 | 3  2   1818  9   478 | 6 3 2 | 14 145 14578------------+-------+--------------4   2   6   | 1 7 5 | 8  3   939  37  79  | 2 8 6 | 14 145 1455   8   1   | 3 4 9 | 7  6   2------------+-------+--------------169 146 49  | 8 5 3 | 2  7   1428  14  28  | 9 6 7 | 5  14  37   5   3   | 4 2 1 | 9  8   6`

It's really quite possible that I've already made a mistake, but if I haven't, could somebody please point me in the right direction? I'm looking more to understand how to progress from here, rather than just how to fill in the numbers.

Thanks.
cwgannon

Posts: 6
Joined: 29 January 2006

It looks good so far.

You have a "naked triple" of 146 in column 2 (16, 146 and 14). This means you can eliminate a 4 in the top row. Then, look closely at the remaining 4s in the top box.

Vidar
vidarino

Posts: 295
Joined: 02 January 2006

hi cwgannon & vidar,

you can also achievethe same result with the triple if you look for a hidden double in column 2......

Tarek

tarek

Posts: 2752
Joined: 05 January 2006

I hope I don't come off as an idiot, but here's where the suggestions thus far have gotten me:

Code: Select all
`23  37  247 | 5 1 8 | 6  9   47168 16  5   | 7 9 4 | 3  2   1818  9   47  | 6 3 2 | 14 145 14578------------+-------+--------------4   2   6   | 1 7 5 | 8  3   939  37  79  | 2 8 6 | 14 145 1455   8   1   | 3 4 9 | 7  6   2------------+-------+--------------169 146 49  | 8 5 3 | 2  7   1428  14  28  | 9 6 7 | 5  14  37   5   3   | 4 2 1 | 9  8   6 `

I'm not seeing anything that can be done with the 7's in the top row. What am I missing?

And thanks, already, for the help.
cwgannon

Posts: 6
Joined: 29 January 2006

if you look at column 2

All the 4s are in box 7

As Column 2 must have a 4, you can safely eliminate other 4s in box 7, here we haveonly one elimination r7c3

Tarek

tarek

Posts: 2752
Joined: 05 January 2006

Anyway,

i just noticed the original puzzle, I don't think it's moderate at all..

on the contrary, It is extremely difficult to solve by newspaper standardsespecially when there are multiple solutions..................

I'm curious, how did you make some of the elimination along the way cwgannon ???

Or could you check the starting grid again........

Tarek

tarek

Posts: 2752
Joined: 05 January 2006

Don't worry,

r3c6 must have been 2 & was dropped out....

Tarek

tarek

Posts: 2752
Joined: 05 January 2006

tarek wrote:if you look at column 2

All the 4s are in box 7

As Column 2 must have a 4, you can safely eliminate other 4s in box 7, here we haveonly one elimination r7c3

Tarek

That hint was all it took for me to solve the rest. I just wish I'd spotted it earlier myself.

As it turns out, this puzzle was actually rated as "Hard. Like Diamonds." by the Daily Cardinal in Madison. I figured I'd just label it as a moderate one, as it seems to be compared to some of those I've seen here.

Thanks again for the help. I appreciate it.
cwgannon

Posts: 6
Joined: 29 January 2006

### Moderate puzzle for a beginner

tarek wrote:"..you can also achieve the same result with the triple if you look for a hidden double in column 2...."

Adding to your correct comment, when four clues ('given' numbers) appear, as in this case, in a unit (row, column or box) and a naked triple exists in that unit, then after eliminating these three candidates if existing in other cells of that unit, the remaining candidates in that unit will always form a naked pair .

I normally find it "easier" to spot naked triples than hidden pairs but that's just me. You are correct but thought I'd throw this in.

Cec
Cec

Posts: 1039
Joined: 16 June 2005

### Re: Moderate puzzle for a beginner

cecbevwr wrote:I normally find it "easier" to spot naked triples than hidden pairs but that's just me.

I find it easier to even spot naked quads than a hidden pair, so I certainly don't think it's "just you".

Ron
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

After removing 4 in r1c2 because of the hidden pair 37 in col 2, the locked candidate 4 in r1c3 f3c3 eliminate the 4 in r7c3.

Nothing but singles after that.

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

Looking at the wrong grid, so comment deleted. Sorry, Ron
Last edited by ronk on Sun Mar 05, 2006 6:08 am, edited 1 time in total.
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

Code: Select all
`23  347 247 | 5 1 8 | 6  9   47 168 16  5   | 7 9 4 | 3  2   18 18  9   478 | 6 3 2 |*14*145*145+78 ------------+-------+-------------- 4   2   6   | 1 7 5 | 8  3   9 39  37  79  | 2 8 6 |*14*145*145 5   8   1   | 3 4 9 | 7  6   2 ------------+-------+-------------- 169 146 49  | 8 5 3 | 2  7   14 28  14  28  | 9 6 7 | 5  14  3 7   5   3   | 4 2 1 | 9  8   6 `

You may think this is funny, but the first thing I saw when looking at this grid was the very obvious MUG formed by the 145 in the starred cells. This forces r3c9 = 78 which solved the 5's. It didn't exactly crack the puzzle, but it did get rid of some clutter.
Myth Jellies

Posts: 593
Joined: 19 September 2005

Code: Select all
`23  347 247 | 5 1 8 | 6  9   47 168 16  5   | 7 9 4 | 3  2   18 18  9   478 | 6 3 2 | 14 145*145*+78 ------------+-------+-------------- 4   2   6   | 1 7 5 | 8  3   9 39  37  79  | 2 8 6 | 14 145*145*5   8   1   | 3 4 9 | 7  6   2 ------------+-------+-------------- 169 146 49  | 8 5 3 | 2  7   14 28  14  28  | 9 6 7 | 5  14  3 7   5   3   | 4 2 1 | 9  8   6 `

In a similar vein to Myth Jellies I saw the uniqueness rectangle of 145's which implied that r3c9=78.

MCC
MCC

Posts: 1275
Joined: 08 June 2005

MCC wrote:In a similar vein to Myth Jellies I saw the uniqueness rectangle of 145's which implied that r3c9=78.

I don't believe that's a valid deduction, since ...
Code: Select all
`1    45    1`

... is one of several possible outcomes not containing 78.

Ron
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

Next