One thing I hate is logically wrong material.
In one of the walkthroughs posted above, there is at least a very obvious logical error, which affects the logical soundness of all steps afterwards.
To prevent readers (if any) from being confused and wasting time pondering about this error, I have to list it below in plain text. It is by no mean personal towards anyone, just my opinion is that a correction of a mistake is also a precious piece of information
to the public audience. It serves as a good example for future solvers on how to avoid similar mistakes, on this or other similar puzzles in the future.
So without further ado, here goes:
In one of the walkthroughs above, someone wrote:
10. 45 rule on N4 1 outie R6C4 = 1 innie R4C1 + 2
10a. R4C1 is part of a 6(2 or 3) cage at R3C1
10b. If 6(2) then R34C1 = {15/24}
or if 6(3) then R3C3 must be part of 22(3) cage at R2C2 => R6C4 = 3 (step 6, only outie for N14) => R4C1 = 1
-> R4C1 = {1245}, R6C4 = {3467}
...
20. 45 rule on N1234 2 outies R4C6 + R6C4 = 11 = [56/83] (cannot be [47/74] which clash with 10(2) cage at R4C5), R4C6 = {58}, R6C4 = {36}, R4C1 = {15} (step 10)
20a. Killer pair 3,6 in 10(2) cage at R4C5 and R6C4, locked for N5
...
22. R4C1 is part of a 6(2 or 3) cage at R3C1 (step 10a) -> 6(2) cage = {15} or 6(3) cage = {23}1 -> R3C1 = {1235}, 1 locked for C1, clean-up: no 9 in R12C1
The glaring mistake here is:
From step 10 it is established that R6C4 = R4C1 + 2. Then in step 20 it is established that R6C4 = [3] or [6]. But somehow R4C1 is wrongfully deduced to be [1] or
[5].
This incorrect claim subsequently leads to a faulty conclusion in step 22 about the 6(?) cage at R3C1 and thus all steps after these ones (from 23 all the way to 56) are built on false logical ground.
The lesson to learn here is when using innie-outies it is very important to subtract accurately, otherwise potentially a lot of time and effort will be wasted. I hope this serves as a good piece of learning material for all solvers of these types of puzzles.
For a walkthrough with completely sound and solid logical steps, just refer to the one in my previous post. There could be minor typo errors (and I will be grateful to anyone who replies and posts about them), but at least I am 100% certain all the logic is 100% correct before I post it out.
Also here I have to state that in the future my PM box will be reserved for only genuinely private matters (for example sharing private materials with my friends). So anything considered as public (such as what I posted in the forum to the public audience), I will not reply. Such messages will be considered spam and will be promptly ignored. I think every member has a right to decide how he/she would like to use the PM box, not to mention how he/she would like to express his/her opinions in public.
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