The New Sudoku Players' Forum

[julnjake]

Can someone help with first big number please?
Thanks!

[7b53]

cute puzzle to do without pencil markings.
wonder how long it takes to spot the triple of (1,4,9) at column 4.

easier to spot the pair of (1,5) at box 8. (r7c5 and r9c4=pair of 1,5)
first number... r6c4=3 (unique in column 4)

[julnjake]

There is an option to put in candidates I just don't use it. Guess I have to do more reading on solving tips because I don't understand how you figured that out. Thanks though! And btw I love the app!!!!!

[JasonLion]

You need pencil marks, either written down or memorized, to solve a puzzle at this difficulty level. Once all of the valid pencil marks are known, solving it isn't all that difficult, requiring locked candidates and either a naked triple or a hidden pair.

[ArkieTech]

Code: Select all

 *-----------*
 |..7|A3.|.9.|
 |3..|A.5|2..|
 |...|A.2|8..|
 |---+---+---|
 |.4.|...|3..|
 |...|8.1|...|
 |..6|...|.5.|
 |---+---+---|
 |..8|6C.|...|
 |..5|7..|..1|
 |.9.|B2.|4..|
 *-----------*

AAA cannot contain the value 8 or 6
so it must contain 149

this means B cannot be a 1

so C must be a 1

since the three cells marked A must contain only three values it is called a locked set
the values 149 cannot appear anywhere else in the fourth column or second box.

[Pat]

There is an option to put in candidates,
I just don't use it

this puzzle can be solved without lists of "candidates"

as 7b53 pointed out,
b8 has a "hidden" duo {1,5}
which solves the c4 3

or going to a trio --

• in b2, "hidden" trio {6,7,8} solves the c5 1
• or in c4, "hidden" trio {2,3,5} solves b8 1
  
  

  Code: Select all

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


if you list the possibilities in each cell,
you may notice the c4 "naked" trio ={1,4,9} ( instead of the c4 "hidden" trio )
-- which would give the same result

[7b53]

or going to a trio --

• in b2, "hidden" trio {6,7,8} solves the c5 1
• or in c4, "hidden" trio {2,3,5} solves b8 1
  
  

  Code: Select all

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


if you list the possibilities in each cell,
you may notice the c4 "naked" trio ={1,4,9} ( instead of the c4 "hidden" trio )
-- which would give the same result

nice alternative ways to spot them.
either {2,3,5} at Box 2 toward column 4
or at column 4 {6,7,8} to Box 2

one can spot these triples in no time.

cheers