The New Sudoku Players' Forum

[schlibs]

I'm working through the New York Post book (Wayne Gould) Vol. 1 and I'm stuck on 36. And it's real frustrating because it's only a difficult and i've had little to no problem with the puzzles before and after this. Must be something I'm missing but I can't for the life of me figure it out. I'd like to think there is some advanced technique I'm not aware of to solve this but I'm just not sure. Please take a look and tell me what you think...

**9 7** ***
5** 8*2 7*9
8** *1* **6

**1 67* 4*5
*** *4* **7
746 **8 2**

4** *9* **8
692 38* *74
*** 4*7 9**

I'm not asking for anyone to solve the rest just the next step from which I can work off of. Thanks a lot.

[Nick67]

just a brief hint: study the middle box (box #5) -- you can make progress
w/o using an advanced technique.

[Doyle]

There's an obvious and immediate placement in block 5, which then leads to placements in block 8. You don't need to enter all candidates to find them. That should get you going.

[Edit: Nick saw it first, same hint.]

[schlibs]

found it, thanks.

don't know how I missed it

[krazyarde]

I'm working through the New York Post book (Wayne Gould) Vol. 1 and I'm stuck on 36. And it's real frustrating because it's only a difficult and i've had little to no problem with the puzzles before and after this. Must be something I'm missing but I can't for the life of me figure it out. I'd like to think there is some advanced technique I'm not aware of to solve this but I'm just not sure. Please take a look and tell me what you think...

**9 7** ***
5** 8*2 7*9
8** *1* **6

**1 67* 4*5
*** *4* **7
746 **8 2**

4** *9* **8
692 38* *74
*** 4*7 9**

I'm not asking for anyone to solve the rest just the next step from which I can work off of. Thanks a lot.

I was trying to solve your puzzle just to see if I could do it as I am new to Sudoku puzzles. I went this far and got stuck.

**9 7** 8*2
5*4 8*2 7*9
827 *1* **6

2*1 67* 4*5
9** 24* 6*7
746 **8 2**

47* *96 *28
692 38* *74
*** 427 96*

I don't know all the terminology for different solving techniques but simply solve by process of elimination. I did finally solve puzzle by taking a quess at putting a 3 in r1c1 but would like to know by what reasoning I could have used to realize that that was the only number possible in that space. Please state answer in simple terms.

[Karyobin]

Okedoke. Taking a slight risk here, the first thing you need to do is go through every cell and fill in, in pencil (writing very small), what numbers could go there. Then read the following paragraph a few times and ask any questions about bits you don't get. I've tried to explain it thoroughly.

In the bottom row (Row 9) there is a Naked Pair in the first and last cells, (row 9 column 1 and row 9 column 9, hereby referred to as r9c1 and r9c9). That means that these cells both contain the possibilities (candidates) 1 and 3. So, if these two cells can only be 1 or 3, then they must be 1 or 3. So, 1 or 3 can't be anywhere else in that row. So cross out all other 1's and 3's in row 9 (r9c2 and r9c3). This gives you another Naked Pair in cells r9c2 and r9c3, i.e. {5,8}. Once again, 5 and 8 must be in these two cells, so there can't be a 5 in r7c3.

So r7c3 must be a 3.

Therefore r9c1 is a 1 and r9c9 is a 3, etc...

[Pat]

I'm working through the New York Post book (Wayne Gould) Vol. 1 and I'm stuck on 36. And it's real frustrating because it's only a difficult

Code: Select all

 . . 9 | 7 . . | . . .
 5 . . | 8 . 2 | 7 . 9
 8 . . | . 1 . | . . 6
-------+-------+------
 . . 1 | 6 7 . | 4 . 5
 . . . | . 4 . | . . 7
 7 4 6 | . . 8 | 2 . .
-------+-------+------
 4 . . | . 9 . | . . 8
 6 9 2 | 3 8 . | . 7 4
 . . . | 4 . 7 | 9 . .

I was trying to solve your puzzle.
I went this far and got stuck:

Code: Select all

 . . 9 | 7 . . | 8 . 2
 5 . 4 | 8 . 2 | 7 . 9
 8 2 7 | . 1 . | . . 6
-------+-------+------
 2 . 1 | 6 7 . | 4 . 5
 9 . . | 2 4 . | 6 . 7
 7 4 6 | . . 8 | 2 . .
-------+-------+------
 4 7 . | . 9 6 | . 2 8
 6 9 2 | 3 8 . | . 7 4
 . . . | 4 2 7 | 9 6 .

hi, krazyarde, just saw your question

at the point you reached,
the 1 for box TR [ Top-Right ] is in column 8,
eliminating 1 elsewhere in that column;
hence, the 1 for box MR [ Middle-Right ] must be in column 9.

now place the 3 in c9,
the 3 in c7,
the 3 in r7,
the 1 in r5,
finish r8 and r7 and c1

place the 3 in c6, the 3 in r6, the 3 in r5
finish r4 and r5 and r9

notice that r2c8 must be 1 as all other symbols are taken. (when i look at boxes, rows, columns, i do sometimes forget to reverse my focus and look at individual cells! which is why Karyobin proposed that you actually write in the lists of all possible symbols for each cell)

etc

( no need to find any duo or trio - but much more fun if you do )

- Pat