| View previous topic :: View next topic |
| Author |
Message |
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
 Posted: Mon Aug 14, 2006 2:29 pm Post subject: Sunday Times 13 aug 06 |
 |
|
At this crunch point
600 304 750
300 020 690
007 060 380
009 002 100
023 401 570
000 600 200
976 010 423
518 243 967
030 976 815
A solution can be reached by considering the impact of a 1 at r6 c1.
immediately r6c6 becomes 7, r4 c4 becomes 8 and r5c5 9
now r5c1 is 8 and we have 89 in rows 4 and 5 as well as 89 in col7 all pressurising r6c9 to hold both 8 and 9 which it can't do
Hence 1 must lie ar r3c1 ...and so on.. to the solution.
So knowing that Sudoku pro's hate forcing functions, can anyone offer me the name and logic behind the solution you would use!!!!
Note : I have removed an 8 in r2c2 that was not apparent at the crunch point!
Last edited by George Woods on Mon Aug 14, 2006 11:56 pm; edited 1 time in total |
|
| Back to top |
|
 |
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Mon Aug 14, 2006 2:41 pm Post subject: My observations |
|
|
In the position you posted, you can easily solve R5 beginning with <8> in C1. Then, you can solve the remaining <9>'s, and then the <8>'s. Then <7>, then <4>, then the rest.
It is all naked singles, except for one hidden single ("pin") on <9>.
Keith |
|
| Back to top |
|
|
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
| Posted: Mon Aug 14, 2006 11:54 pm Post subject: a mistake in my original posting |
|
|
| Sorry for wating your time maybe-- I made an error in my posting -- the 8 in box1 should not be there (although curiously this 8 appears in the same place with either position of the 1 in col 1) - SO IS THIS A CLUE TO THE PROPER TECHNIQUE FOR SOLVING THIS ONE? |
|
| Back to top |
|
|
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Tue Aug 15, 2006 12:51 pm Post subject: |
|
|
The same thing applies: Solve row 5, then find the 8 in row 2, etc.
Keith |
|
| Back to top |
|
|
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
| Posted: Tue Aug 15, 2006 2:36 pm Post subject: Yet another silly |
|
|
| The solution as you point out is so easy that I thought "It can't be!" So to make sure I had recorded the crunch point correctly, I went back to the original puzzle and repeated the solution from scratch to the crunch point and guess what ANOTHER STUPID ERROR IS REVEALED ON MY PART -- the 2 in box 4 should not be there !!!!!!!!!!! |
|
| Back to top |
|
|
David Bryant
Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado
|
| Posted: Tue Aug 15, 2006 4:26 pm Post subject: It's still pretty simple |
|
|
OK, George, I guess this is the "crunch point" (assuming I've followed all this correctly}.
| Code: | 600 304 750
300 020 690
007 060 380
009 002 100
003 401 570
000 600 200
976 010 423
518 243 967
030 976 815 |
-- The only apparent possibilities at r6c3 are {1, 4, 5}.
-- The only possibilities at r6c8 are {3, 4}.
-- The "8" in column 2 must lie in box 1. So the only possibilities at r6c2 are {4, 5}.
-- There's a naked pair {8, 9} in column 5 (r1c5 & r5c5). This reveals a hidden pair {3, 5} in r4c5 & r6c5.
Counting this up we find the triplet {3, 4, 5} in r6c2, r6c5, and r6c8. So the sole candidate at r6c3 is a "1", and it's a piece of cake from there. dcb
PS Please post the original puzzle when you have a question like this one, George -- it will be more fun for the rest of us that way.  |
|
| Back to top |
|
|
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
| Posted: Wed Aug 16, 2006 10:57 am Post subject: |
|
|
Thanks
Once again we find, unlikely though it seems, that the key lies in the least populated row,column, or box. I suppose seeing the very obvious 35 and 34 in the row should have prompted the though "Bet there is a 45 along here" - but it's so easy to see it after the event!!!! |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
