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Advice for Newbies and Regulars - Updated September 2007

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Joined: 11 Aug 2006
Posts: 300
Location: Lethbridge, Alberta

PostPosted: Fri Mar 02, 2007 6:15 pm    Post subject: Advice for Newbies and Regulars - Updated September 2007 Reply with quote

In his message with Assassin 37 Ruud wrote "If you haven't done Assassins yet, now is the time to step in".

It was a straightforward Assassin although I took a long time to see one of the key moves.

If you are new to Assassins, I would recommend either that you start with Assassin 40 or work through the puzzle archive from the beginning, which is what I did when I started on Assassins in August 2006. The early ones are definitely easier than most more recent ones.

I found Assassin 18 to be the first difficult one. I got stuck on this one and got a hint from Ed. I didn't quite understand what he was getting at, since a good hint must make one think hard, but it pointed me to a similar thing in a different part of the puzzle and I then managed to solve it. It was quite illuminating to read Ed's walkthrough and see what his hint had actually meant.

Since the title of this message is advice, here it is

1. Don't be afraid to try Assassins. If you are a newcomer to Killers the first twelve Assassins are good ones to start with. Ed’s Rating thread lists more recent Assassins and forum puzzles under various levels of difficulty. The ones rated 0.75 are good starting ones.

2. Always read the message that Ruud puts above each puzzle.

3. Write a walkthrough while you are solving each Assassin, even if it's only notes on scraps of paper; I do mine in a Word file while I'm solving the puzzle.

4. After you have solved an Assassin, or at least tried to solve it, read the walkthrough(s) that are posted on this forum. I think there are walkthroughs for all except Assassins 1, 2, 5 and 10. It's good to see how other members of the forum have solved puzzles and if you work through the posted walkthroughs you should learn some techniques. Some walkthroughs are basically how a puzzle was solved; my ones were originally like that but now if I spot a move that I ought to have seen earlier, I usually insert it there. Other walkthroughs try to show the most direct route to solve the puzzle.

5. Many people on this forum use SumoCue, which is available as a free download from this website.

6. There are also other harder variants of some Assassins and some other puzzles posted on this forum. Once you have solved a few Assassins, you might like to try Ruud's Chevron Killer, Peter's NonCon and Peter's CDK. The other ones are generally much harder but are worth trying when you have gained more experience. Most of these puzzles have a code string that can be directly imported into SumoCue.

7. Once you have become confident and are solving the current puzzles, please join the forum and post your walkthrough if you are the first for a puzzle or if you have a significantly different solving path, particularly if it avoids difficult steps. Most of the regulars on this forum first posted walkthroughs here.

8. If you post a walkthrough while a puzzle is still active (before the next Assassin has been posted), please use tiny text. The Font Size for Tiny sets Size = 7. In the text area you should then change this to Size = 1, then type or paste your walkthrough between the two sets of []. After the solution has been posted in the puzzle archive, you should delete the tiny text commands to convert your walkthrough to normal text.

For shorter comments on active puzzles there is also the "cloaking method". For details of this see the final part of starting at (PS). As Ruud says there, tiny text is better for full walkthroughs.

9. Don't be afraid to contact regular posters to the Assassin forum by using the Private Message (PM) facility. This is a very friendly forum and people are very helpful.

10. Enjoy the challenge of Assassins and have fun!

11. You need to be a registered member and to have signed in to be able to reply to messages on the forum or send private messages to other forum members. Registration is a simple process. It includes a user profile. That can be edited at a later date.

This message has now been updated to address things that weren't covered in the original advice.

The best feedback I received while working on the update was "I guess I just adapt to the forum". An excellent suggestion!

TAG Solutions
The original idea for tag solution was - "the 'tag' being like in 'tag-team' wrestling - one person starts, then another takes over".

Basically, the unwritten 'rule' is that as soon as one forum member publishes a partially-completed puzzle, asking for assistance, he or she is implicitly starting off the tag. The idea then is for someone else to pick up the tag and 'run' with it.

Wait until a tag solution is finished before posting an individual walkthrough.

The puzzle creator will only take part in a tag solution if they don't know how to solve it. However they may post hints if the tag seems to be getting stuck.

A walkthrough should be easy to follow for a newbie to Killers. Some people give more detail than others - it's a matter of personal preference. The important thing is that it is easy to follow. Preliminary steps are usually given unless you state that they have been omitted or there is a candidates diagram.

Try to avoid putting too much into preliminary steps. Simple combination clashes, locked candidates for rows/columns/nonets and common peer eliminations seem to be acceptable. Killer pairs and more complicated combination clashes should be given as separate steps after the preliminary ones.

One good suggestion, received in response to the draft that I posted on the forum was "I always try to use my preliminaries to set the grid to what SumoCue shows you when you open marks. That is why I tend to keep the locked candidates till the end of the prelims (like 17(2) or 23(3) cages). I guess I like to keep things as simple as possible in the beginning. Otherwise you have to start with awkward notations like [18/27]/{36/45}".

Include clean-up effects resulting from candidate eliminations in other cells; don’t assume that someone going through your walkthrough will do them ‘automatically’.

A walkthrough should be your own work - not software solver aided. If a solver gave you some help or showed a shortcut at a certain spot, say that the solver did that.

The creator of the puzzle doesn't publish their own walkthrough unless other players have failed to solve the puzzle or haven't posted a walkthrough.

My personal opinion is that all Assassins, except for a few very early ones, and all forum puzzles ought to have posted walkthroughs.

If you find a mistake in a solver's walkthrough, and it makes the solution invalid, point this out on the forum or by private message. Some solvers prefer you tell them by private message, others don't mind on the forum. Look at past posts to tell which that individual prefers. But they all want to know! If you can see a valid way to get around the problem, suggest that too. If you notice any small errors, point those out. If there is something you liked - tell them!

Where feedback has been provided by PM and used for editing it's good 'netiquette' to give credit except for minor points such as typos.

Ruud’s Weekly Assassins have their solutions posted in the Archive. If you are the first to post a walkthrough for a forum puzzle it is a good idea to give the solution at the end of your walkthrough so that others can check their solutions. There is no need to do this when the puzzle is a variant of the original Assassin which has the same solution.

Walkthrough Notation
There is no specific way to write walkthroughs. We each have our own styles which, in my opinion, makes this forum more interesting.

All steps should be numbered. There should be a blank line between numbered steps but not within a sequence of sub-steps. It is a matter of personal preference whether to number the preliminary steps or to give them as a group at the beginning and then start numbering after that.

Rows, columns and nonets are usually identified using the letters R, C and N (in either upper or lower case according to personal preference) followed by a number or numbers, for example R1C23.

Cages which are within one row, column or nonet are normally identified by their cells or by the nonet. Other cages that are in more than one nonet are identified either by their upper-left cell (the cell which contains the cage total in the puzzle diagram), for example 21(4) cage at R6C8, by the cells they are in, for example r6c8+r7c78+r8c8, or by the nonets they are in, for example 21(4) n69.

Where there are two similar cages in the same part of the grid, for example Assassin 68 has a 19(3) cage completely in N6 and another at R6C9 that is partly in N6, it is clearer to refer to both cages by their cells.

When listing the options for a cage, partial cage or split cage, {} is used to list options where the order of the candidates is not known. [] is used where the order of the candidates, or some of the candidates, is known. When using [] for multi-row or multi-column cages, the candidates should be listed fom left-to right, top-to-bottom.

{} and [] can both be used in a list of options where the order of some of the candidates is known.

When listing options for a cage, alternatives should be separated by / or |. Other separators such as I should not be used; they can make it really difficult to read a walkthrough. My personal opinion is that /, rather than |, makes it easier to read a set of combination options.

When candidates are locked for particular cells, for example because of a Naked Pair, this should be indicated by saying "locked for …" or "not elsewhere in … (sometimes abbreviated as n/e)".

When a value is fixed in a cell, you should not say "not elsewhere in row/column/nonet". An exception is for Killer-Xs where some walkthroughs will say "locked for D/” or “locked for D\". An alternative might be to say at the beginning of the walkthrough "Remember to eliminate candidates when cells on one or both diagonals are fixed". When working through a walkthrough with an automated solver such as SumoCue these eliminations will be made automatically. However not everyone uses an automated solver.

-> is used to indicate that something follows from the previous action although, when there is a string of things they are often separated by commas.

Some walkthroughs use <> or !=, meaning "does not equal", to indicate that a value has been eliminated from a cell or a combination/permutation has been eliminated from a cage. My personal opinion is that <> is easier to read than !=. <> is also used more often on this forum. The other normal method is to give eliminations in words, for example no 8 in R2C4.

The use of [] after a set of combination options, for example {149/167/248} = [1/2, 4/6, ...], shows alternatives that must be present in the cage. These are useful when a later step eliminates combinations from other cages that clash with these alternatives. If the alternatives are not used later, they aren’t normally listed. In the example 1/2, 4/6 will be used later; ... indicates that other alternatives won't be used.

A good web page for further explanation of notation is Killer Lingo However some of the notation used on that page is not consistent with this forum and should be avoided. For example describing a cage as 21/4, rather than the normal 21(4), is confusing because it suggests an alternative.

If you use advanced techniques, particularly if they are expressed in Eureka notation, make sure that the result(s) of these steps are clearly stated so that people who don’t know these techniques can understand what has been done and, if they wish, try to work out that step by alternative methods.

Killer Terms

Terms commonly used in walkthroughs (with their abbreviations, where used on this forum) include

Naked Single (NS), Naked Pair (NP), Naked Triple (NT), etc.
Hidden Single (HS), Hidden Pair (HP), etc.
Killer Pair (KP), etc.
45 rule, Innies, Outies, Innies/Outies (O-I is used to specifically mean Outies minus Innies, maybe I-O could be used where the Innies are larger but I haven’t yet seen that used)
Common Peer Elimination – (CPE); Pointing cells/pairs/triples … is also used.

More advanced techniques are appearing more often in walkthroughs as puzzles get harder and solvers better. The more common ones include X-Wings and Law of Leftovers (LOL).

Innie and Outie Unequal (IOU), see message

Ruud has an excellent Glossary of Sudoku terms on this website at

All posted puzzles should have a diagram. If you post a variant and can generate the code string but not a diagram, please ask for a regular to post a diagram.

Some puzzles are also posted with candidate diagrams. If you do this, please post the candidate diagram below the puzzle diagram. Posting diagrams side by side widens the forum thread and can make it difficult to read other messages in the thread.

Manual solving is what this forum is about. Software solver/helpers have a place, but always say when they have helped. They are generally a last resort.

Newcomers to the forum should remember to read the messages in their Inbox. They may receive replies to forum messages by private messages. If you are signed in, the header area of any forum page will tell you if you have any new messages.

Last edited by Andrew on Wed Nov 07, 2007 4:32 am; edited 6 times in total
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PostPosted: Fri Mar 02, 2007 7:46 pm    Post subject: Reply with quote

Very informative, Andrew!

I'll make this one a sticky. Cool

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