The New Sudoku Players' Forum

[gurth]

GA01 : Present for Claudia

Claudia,

As it was composed on your birthday, maybe you will accept it as a suitable present.

Code: Select all

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


My notes on the day:

ga01 is brilliant pearl, also an emerald!
Emerald now defined for the first time as a puzzle perfect in symmetry of shape AND numeric value of clues.
In its prime form, ga01x has not yet been tested for redundancy, has 23 clues, one naked quad at start then nha.
I think of relaxing the redundancy need for emeralds, but no: they must still be regarded as flawed emeralds.
_______________

ga01 now tested. NO redundant clues! The number of solutions for each removal is consistently low : 3, 7, 7, 8, 13, 13, 15, 15, 17, 29, 47, 54. What does this suggest?
___________________

Gurth

[ronk]

ga01 is brilliant pearl, also an emerald!
...
I think of relaxing the redundancy need for emeralds, but no: they must still be regarded as flawed emeralds.

Just a thought. Can a precious gem -- in the analogized real world -- be both a pearl and an emerald?

[udosuk]

Great puzzle, you can't even apply the Gurth Symmetrical Placement technique at the start!

Not a Diamond though... After the initial naked quad move then r1c8 becomes a backdoor cell under singles... I guess it can't be perfect in every way!

[claudiarabia]

GA01 : Present for Claudia

Claudia,

As it was composed on your birthday, maybe you will accept it as a suitable present.

Code: Select all

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


My notes on the day:

ga01 is brilliant pearl, also an emerald!
Emerald now defined for the first time as a puzzle perfect in symmetry of shape AND numeric value of clues.
In its prime form, ga01x has not yet been tested for redundancy, has 23 clues, one naked quad at start then nha.
I think of relaxing the redundancy need for emeralds, but no: they must still be regarded as flawed emeralds.ga01 now tested. NO redundant clues! The number of solutions for each removal is consistently low : 3, 7, 7, 8, 13, 13, 15, 15, 17, 29, 47, 54. What does this suggest?
Gurth

Hi Gurth,

thank you for your nice puzzle. I wanted to answer earlier because I looked for a short and fine solution I wanted to present but until now I find many chains only and every mass-elimination-technique like swordfish, x-wing or else is not usable because of one candidate disturbing it in the end.
The reason for this is definitely the rotational pattern of the clues and the amount and the placement of the initial numbers in such a refined way which allows a begining with forcing chains only. But I'll keep on trying to find a good candidate to eliminate to make it short.

It was a wonderful birthday present!

Claudia

[claudiarabia]

GA01 : Present for Claudia
As it was composed on your birthday, maybe you will accept it as a suitable present.

Code: Select all

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


My notes on the day:
ga01 is brilliant pearl, also an emerald!
Gurth

Finally I found a neat solution which took me some hours concentration and memorizing a bunch of candidates. With one single forcing chain with many subchains and ramifications I got a situation in which I could finally proceed with singles and pairs only.

I laid a forcing chain upon 1 in r1c9. Here you get in r1 a naked quad of 3569 in r1c2456 leading to the placement of 9 in r2c3 and a pair in r46c8 of 1 and 8. I will spare you all the following paths of the chain which penetrates the whole sudoku. But I will tell you that in the end I got a unique rectangle in r59c46 of the numbers 5 and 9 without any numbers to avoid this rectangle. You call it a naked rectangle then? With this situation 1 in r1c9 is proven to be a false candidate and the puzzle is solved finally. Uff!