... by: Serban

# 666 Basics to 22

3 Step Solution
1. X-chain x=1 => B5<>1
2. C5=6 basics to 31
3. XY-Chain-2468 [A16,B38] =>[B6,A89]<>4 => A6=4 solve

correction
2. Number 6 n=2 e=7 N=30 Nc=65 Ns=54 => C5=D6=6 solve

... by: Dieter

@Henry, you should describe strategies, not record times ;-)

... by: Serban

# 666 Basics to 22
1. Number 8 n=3 e=6 N=17 Nc=5 Ns=1 => E7=8 basics to 32
1a. X chain x=1 =>[J1,B5,C7,H9] <>1 =>[B9,J7]=1 basics to 34
1b. E7=8 & C6=1 solve
1c. E7=8 & E9=2 solve
1d. E7=8 & any[A7,F9]=6 solve
1e. E7=8 & A9=D7=7 solve
1f. E7=8 & G9=J2=9 solve
Note : A1=B6=G2=H8=8
@ Yves thank you Number 2 => B2=E9=2 solve

... by: Henry Laxen

My solver got the solution in 0.3829 seconds.

see nadineloveshenry calcudoku solver
Enjoy

... by: Frans Goosens

#666

Combination 2-digits cells

F1=1 No solution, Undo calculation
F1=9 No solution, Undo calculation
G5=3 ( E5=4 ) Solved,

Total solving time is : 12 sec.
Number of logical steps is : 1415

... by: BGH

3 Step Solution #2 for #666
8 @ H8 Multiple Unit Pairs 33.3
9 @ G9 Cell Pair part of triple pairs 45.7
9 @ F1 Cell Pair 100

This solution is a bit more interesting because of the multiple interacting unit pairs in step 1
Both of my solutions give the same results

... by: BGH

Initial Condition 27.2 for #666 (Solution#1)
9 @ F1 30.8 Cell Pair (1 leads to contradictions)
2 @ F4 38.3 Cell Pair (6 leads to contradictions)
4 @ G5 100 Cell Pair (3 leads to contradictions)

... by: Dieter

#666 - initially populated cells: 22 = 27,2%
No solver used.
basics: %
Strategy: Numbers 5,1,8 occur most frequently, combine two cells.
combinations of C7 = (1,2,5,6,7) and G7 = (2,8)
4 matrices left after basic checks.
C7 /G7 = 5/2 solve with F5=1

Optimization:
C7=5 & F5=1 solve.

... by: Yves

A3=9 & C6=1 & E3=5 Solve

@Serban B2=F4=2

... by: Serban

# 666 Basics to 22

1. Number 2 n=2 e=7 N=29 Nc=52 Ns=12 => B2=F9=2 solve

2. Number 6 n=2 e=7 N=30 Nc=65 Ns=54 => C6=D7=6 solve

... by: numpl_npm

-1r6c1(∵1r6c1 contra.)

... by: numpl_npm

Add to previous post:
-1r9c1(∵1r9c1 contra.)

... by: numpl_npm

7r6c2 (∵ 27r6c45 27r6c89 both contra.)
9r9c2 (∵ 19r9c12 19r9c78 both contra.)
solve