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A relatively easy puzzle for this week, but you will still have to dig a little for the opening move.
I thought this was appropriate since many of us are still working through udosuk's Ray series,
Borge's girlfriends, and manu's challenging A180 (me included).



Enjoy!

Assassin 181


3x3::k:5632:5633:5633:5633:5892:2309:2309:2309:5128:5632:5632:1547:1547:5892:4110:4110:4880:5128:1554:5632:1547:5141:4630:5892:4110:4880:5128:1554:5632:5141:2334:4630:4630:5892:4880:5128:5141:5141:2334:4647:4647:4647:1834:4651:4651:5421:5422:4399:3888:3888:1834:4651:6452:1589:5421:5422:4920:4399:3888:4651:4924:6452:1589:5421:5422:4920:4920:4399:4924:4924:6452:6452:5421:2889:2889:2889:4399:4685:4685:4685:6452:



SS Score: 1.17

An Image for those of you who like to scribble and solve the Joe Casey way:

_________________
Quis custodiet ipsos custodes?

Normal: [D  Y-m-d,  G:i]     PM->email: [D, d M Y H:i:s]

Right ! My more difficult moves were the first ones ! I understand what you mean.
I had fun with finding them. Thanks Ronnie G !

A181 Walkthrough

edit: some corrections :thanks Ronnie G and Andrew

Well, that was entirely too easy for you people. Someone please hurry up & sign the schedule so I can post something a bit more challenging!

P.S. Thanks, Borge, for the much improved image!

Thanks for this fun Killer, Ronnie! Like manu I cracked this Killer right at the start but the moves he and I used aren't trivial, so SudokuSolver's rating sounds right.

A181 Walkthrough:

1. R123 !
a) Outies R1234 = 10(3) <> 8,9
b) ! Outies N1 = 11(2+2): R4C12 >= 5 since (12,13) are Killer pairs of Outies R1234
-> R1C4 = 5, R2C4 = 1 and R4C12 = 5(2) = [14/23/41]
c) 6(3) = {123} -> 2,3 locked for C3+N1
d) 22(3) = {589} -> 8,9 locked for R1+N1
e) 22(5) = {13567} -> R4C2 = 3; 1,5 locked for N1
f) R3C1 = 4 -> R4C1 = 2
g) 9(2) = [45/81]
h) Outies R1234 = 10(3) = {145} -> R5C2 = 4; 1,5 locked for R5+N4
i) Hidden Single: R9C2 = 2 @ C2, R3C2 = 1 @ C2

2. C123
a) Innies C1 = 18(3) = {567} -> R5C1 = 5; 6,7 locked for C1+N1
b) R5C3 = 1 -> R4C4 = 8
c) 20(4) = {2459} -> R4C3 = 9, R3C4 = 2
d) R1C3 = 8
e) 19(3) = {469} since R78C3 <> 3,9 -> R8C4 = 9; 4,6 locked for C3+N7
f) 11(3) = {245} -> R9C3 = 5, R9C4 = 4
g) 21(3) = {678} -> R6C2 = 6; 8 locked for N7
h) R6C3 = 7, R6C4 = 3, R7C4 = 6, R7C3 = 4
i) 17(4) = {1367} -> 1,3 locked for C5+N8

3. R4567
a) 18(3) @ R5 = {279} -> R5C4 = 7; 2,9 locked for R5+N5
b) 18(3) @ N2 <> 1 since R4C5 = (456)
c) Hidden Single: R6C6 = 1 @ N5 -> R5C7 = 6
d) 18(4) = {2358} since R5C89 = (38) -> 8 locked for N6; R6C7+R7C6 = (25)
e) 15(3) = 3[48/57]
f) Naked pair (78) locked in R7C25 for R7
g) 19(3) = 9{28/37} since R7C7 <> 7,8 -> R7C7 = 9

4. C789
a) 18(3) = {378} locked for R9; 3 also locked for N9
b) 19(3) @ N9 = {289} -> 2,8 locked for R8
c) 25(5) = 169{27/45} -> R6C8 = 9; 1 locked for N9
d) 6(2) = {24} -> R7C9 = 2, R6C9 = 4
e) 19(3) @ N3 = 8{47/56} -> 8 locked for C8+N3; R23C8 <> 5,7
f) R6C5 = 5, R6C7 = 2
g) 20(4) = {1379} locked for C9; 3 also locked for N3
h) 16(3) = {457} since R23C7 = (457) -> 5 locked for C7; CPE: R2C89 <> 4,7

5. Rest is singles.

Thanks Ronnie. I enjoyed your latest Assassin!

My breakthrough was basically the same as Afmob's but it took me a few steps to find it. Some of my earlier steps seemed a bit irrelevant although one proved to be useful later; they could however be useful for a harder puzzle using the same cage structure so that's another reason why I've kept them in. I found manu's way to crack this puzzle very interesting. I'd never have thought to look at the 22(5) cage so early; maybe I ought to learn to look at such things earlier.


Here is my walkthrough for A181.

Prelims

a) R34C1 = {15/24}
b) 9(2) cage at R4C4 = {18/27/36/45}, no 9
c) 7(2) cage at R5C7 = {16/25/34}, no 7,8,9
d) R67C9 = {15/24}
e) 22(3) cage at R1C2 = {589/679}
f) 9(3) cage at R1C6 = {126/135/234}, no 7,8,9
g) 6(3) cage at R2C3 = {123}
h) 19(3) cage at R2C8 = {289/379/469/478/568}, no 1
i) 21(3) cage at R6C2 = {489/579/678}, no 1,2,3
j) 19(3) cage at R7C3 = {289/379/469/478/568}, no 1
k) 19(3) cage at R7C7 = {289/379/469/478/568}, no 1
l) 11(3) cage at R9C2 = {128/137/146/236/245}, no 9

Steps resulting from Prelims
1a. 9 locked in 22(3) cage at R1C2, locked for R1
1b. Naked triple {123} in 6(3) cage at R2C3, CPE no 1,2,3 in R2C12

2. 45 rule on C9 3 innies R589C9 = 19 = {289/379/469/478/568}, no 1

3. 45 rule on R1234 3 innies R3C4 + R4C34 (which form a hidden cage because they “see” each other) = 19 = {289/379/469/478/568}, no 1, clean-up: no 8 in R5C3
3a. 45 rule on R1234 3 outies R5C123 = 10 = {127/136/145/235}, no 8,9

4. 45 rule on R6789 3 innies R6C67 + R7C6 (which form a hidden cage because they “see” each other) = 8 = {125/134}, clean-up: no 1 in R5C7
4a. Max R6C7 + R7C6 = 7 -> min R5C89 = 11, no 1 in R5C8

5. R5C123 (step 3a) = 10
5a. 45 rule on C12 2 innies R19C2 = 1 outie R5C3 + 10
5b. Min R19C2 = 11, no 1 in R9C2

6. 45 rule on R6789 3 outies R5C789 = 17
6a. 45 rule on C89 2 innies R19C8 = 1 outie R5C7 + 3
6b. Max R5C7 = 6 -> max R19C8 = 9, no 9 in R9C8

7. 45 rule on N1 4(2+2) outies R12C4 + R4C12 = 11
7a. Min R12C4 = 6 -> max R4C12 = 5
7b. R4C12 = {14/23} (cannot be {12/13} which clash with R5C123), clean-up: no 1 in R3C1
7c. R4C12 = 5 -> R12C4 = 6 = [51], clean-up: no 4 in R5C3
7d. 22(3) cage at R1C2 = {589} (only remaining combination), 8,9 locked for R1 and N1
7e. Naked pair {23} in R23C3, locked for C3 and N1, clean-up: no 6,7 in R3C4, no 4 in R4C1
7f. R4C1 = {12} -> R4C2 = {34}

8. R5C123 (step 3a) = {145/235} (cannot be {127} which clashes with R4C1, cannot be {136} which clashes with R4C12), no 6,7, 5 locked for R5 and N4, clean-up: no 2,3 in R4C4, no 2 in R6C6
8a. Killer pair 1,2 in R4C1 and R5C123, locked for N4
8b. Killer pair 3,4 in R4C2 and R5C12, locked for N4
[Or steps 8a and 8b could be given as naked quint {12345} in R4C12 + R5C123, locked for N4.]

9. 22(5) cage at R1C1 = {13567} (only remaining combination) -> R4C2 = 3, R4C1 = 2 (step 7b), R3C1 = 4
9a. R5C2 = 4 (hidden single in N4), R3C2 = 1, R9C2 = 2 (hidden singles in C2), clean-up: no 3 in R6C6
9b. Naked pair {15} in R5C13, locked for R5
9c. 5 in N1 locked in R2C12, locked for R2

10. 21(3) cage at R6C2 = {579/678}, 7 locked for C2
10a. 7 in N1 locked in R12C1, locked for C1

11. 21(4) cage at R6C1 = {1389} (only remaining combination, cannot be {1569} which clashes with R5C1), locked for C1 -> R5C12 = [51], R4C4 = 8
11a. R2C2 = 5 (hidden single in N1)
11b. 21(3) cage at R6C2 (step 10) = {678} (only remaining combination), locked for C2 -> R1C23 = [98]
11c. 8 in N4 locked in R6C12, locked for R6

12. R5C12 = [54] = 9 -> R3C4 + R4C3 = 11 = [29], R23C3 = [23], R6C1 = 8
12a. Naked pair {67} in R6C23, locked for R6

13. 18(3) cage in N5 = {279/369}, 9 locked for R5 and N5
13a. R6C8 = 9 (hidden single in R6)
13b. 19(3) cage at R2C8 = {478/568}, no 3, 8 locked for C8 and N3
13c. R5C9 = 8 (hidden single in R5)

14. 9 in C9 locked in R23C9, locked for N3
14a. 20(4) cage at R1C9 = {1379/2369} (cannot be {1469/2459} which clash with R67C9), no 4,5, 3 locked for C9 and N3
14b. Killer pair 1,2 in 20(4) cage and R67C9, locked for C9

15. 9(3) cage at R1C6 = {126/234}, 2 locked for R1
15a. 45 rule on R1 3 innies R1C159 = 14 = {167/347} = {67}1/[743], no 3 in R1C5, no 6,7 in R1C9

16. R9C2 = 2 -> R9C34 = 9 = [54/63]
16a. 4 in C3 locked in R78C3, locked for 19(3) cage at R7C3, no 4 in R8C4
16b. 19(3) cage at R7C3 = {469} (only remaining combination) -> R8C4 = 9, R78C3 = {46}, locked for C3 and N7 -> R6C23 = [67], R9C3 = 5, R9C4 = 4

17. R6C4 = 3 -> R67C5 = 12 = [48/57], R7C4 = 6, R5C4 = 7, R78C3 = [46], clean-up: no 2 in R6C9
17a. R6C7 = 2 (hidden single in R6), R1C8 = 2 (hidden single in R1), clean-up: no 5 in R6C6
17b. R6C7 = 2 -> R67C6 = [15] (step 4), R5C7 = 6, R5C8 = 3
17c. Naked pair {78} in R7C25, locked for R7
17d. Naked pair {12} in R7C89, locked for R7 and N9

18. R6C3 + R7C4 = [76] = 13 -> R89C5 = 4 = {13}, locked for C5 and N8
18a. R8C6 = 2 (hidden single in N8), locked for C6 -> R5C56 = [29]
18b. R8C6 = 2 -> R78C7 = 17 = [98]

19. 6 in R4 locked in R4C56, locked for 18(3) cage at R3C5, no 6 in R3C5
19a. 18(3) cage at R3C5 = {468/567}, no 9
19b. R2C5 = 9 (hidden single in C5)
19c. Naked pair {78} in R37C5, locked for C5
19d. R1C1 = 7 (hidden single in R1), R2C1 = 6

20. 20(4) cage at R1C9 (step 14a) = {1379} (only remaining combination), locked for C9 -> R9C9 = 6, R7C9 = 2, R6C9 = 4

and the rest is naked singles.