Str8ts on iOS and Android   Welcome to the home of Str8ts Caution!
 
Print Version
Str8ts Explained
Play Here...
Android & Apple Apps
Our Service
Str8ts for iOS and Android
Order Str8ts Book 2
Order Now!
1 to 25 - on the iPhone
 
Extra Puzzle Series
For those of us in self-isolation or quarantine with too much time on their hands, I have expanded the Str8ts puzzles to a new 'every two-days' series. Check out the new player. Stay well.
Archive
Since there has been interesting strategy discussion on these puzzles and by popular request, I have opened an archive on the last thirty weeks. The discussion section is open for continued posting.
Share and Enjoy
Puzzles 1 to 250 are available as Puzzle Packs, just $5.49. Pack 3, 4 and 5 just released!

Discussion...
Latest threads are now at the top.
In addition, posts you have NOT read are in normal colors, older ones are in grey.
Please email me if you experience problems or bugs. Cheers, Andrew Stuart


Your Name or Handle

Your comment or question

Enter these lettersarrow

Please keep your comments relevant to this article.
To state your solve time use the smaller form at the top right of this page.

Line breaks and paragraphs are automatically converted. No need to use <p> or <br> tags.

No full solutions please!



by:mparmen

Reply to this post
Easy but enjoyable.

by:Jens

 
Discussion of Andrew's Extreme Str8ts Puzzle, Quarantine Edition #201, May 6 - May 7

 

by: jk

 
 
pure logic (4*)

 

by: jgrab

 
 
An easy one (9 min).

 

by: morl

 
 
One setti is enough.

 

by: Onkel Otto

 
 
singles and 1 x-wing, setti not needed

 

by: Joe

 
 
Basics and one small setti in 11 min

 

by: mparmen

 
 
Easy but enjoyable.

 

by: hp

Add to this thread
 
Bca/setti 7 enough to solve

by:Jens

 
Discussion of Andrew's Extreme Str8ts Puzzle, Quarantine Edition #200, May 4 - May 5

 

by: jgrab

 
 
Was lucky with the right decision on D7. Didn't follow the alternative contradiction.

 

by: jk

 
 
bca:7&4&2 sure; 6 possible in col 7 (row D,G,J); I started with 7 impossible in col 7 (-> 6 sure in d) and in row G (-> x8, 6 sure in J, 5 imp. in J) -> solution (I did not proof the alternative)

 

by: Marya

 
 
@jk: I can't follow your argument. I suppose there must be a typo: 7 is a given digit in col 7.
According to my analysis, 7 is a must in all rows and colums (except H / 3 of course), and 6 is possible in rows D, G and J and in col's 6 and 7.

 

by: jk

 
 
@Mary: Sorry, it's my mistake; correct is: ..I started with 6 impossible in col 7 ..

 

by: jgrab

 
 
After CE, D7=28. If D7=2, E3=1, E8=7; no 1 in row G, so 8 in G4 (naked double in col 4), x-wing on 8 DH12, so no 8 left for row F.

 

by: Jens

 
 
@jgrab: The decision in E8 is similar like decision in D7, having the same result.

 

by: MrL

Add to this thread
 
After decision in D7 and/or E8, as jgrab and Jens wrote above, there is still a lot of work to do: lot of singles, x-wing(s) and finally a 3-fish to solve this enormous beast.

by:hone

 
The current zodiac symbol

is.gd/hone567_Taurus

 

by: Leren

 
 

Taurus the Bull is mortally wounded by the Sword of Orion :)

 

by: jgrab

 
 
Very nice, thanks! A perfect medium level of difficulty.

 

by: BP

Add to this thread
 
Great pattern. Like jgrab, with an UR.

by:Klaus

 


good one

 

by: Klaus

Add to this thread
 

wrong post

by:authority

 
Don't post here!

 

by: Klaus

Add to this thread
 


good one

by:Klaus

 

just CE, not even Setti is needed Mr. Setti

 

by: Jens

 
 
Not even your post is needed Mr. Klaus -
Pls. mind my post at the bottom of this page.
Btw: It's no shame, but Settis comments are always the same -

 

by: Klaus

 
 
Hi Jens,

maybe not needed but i like it.

i am somewhat paranoid with people who tell me what do do where, always provokes me to do it in a different way.

ride on.

 

by: Jens

 
 
Aye aye, Sir!

 

by: Setti

 
 
I can not see the original comment, but at least 2 users comments here as Setti. So Setti's comments must not be always the same. :)

As of me, I comment rarely, and try not to tell what to do.

Setti, the user, the rule is named after


 

by: Klaus

 
 
Hi Setti,

nice to see that you still stick around.

You brought a lot of joy to many people here, including myself. i still remember your post, many years ago, where you first mentioned the reasoning behind your rule, and the breathless silence directly after, and the first response "wow, that is strong". think it was Setti on 8 if i'm not mistaken.

 

by: Setti

 
 
Hi Klaus,

thank you.

I remember also. :) It could be 8, also not sure about it. It was more than 10 years ago, but str8ts is still my favourite variant of sudoku.

Andrew made it possible with many people here who help solving. Glad to have a part to play in it.

Your comment made me happy, thank you again.

 

by: Jens

Add to this thread
 
Hi Setti,

congratulation to over 10 jears Setti Rule. Your rule is the same time basis of BCA, too. Both helps to come through difficult str8ts.

by:Leren

 


is.gd/Leren_567_BX2

 

by: Toni

 
 
As usual "the big brother" is a bit harder at the end, yet, the start is even easier than in the first BX puzzle

 

by: witch

 
 
very nice - no chain

 

by: BP

Add to this thread
 
Much harder than BX1 for us, needed a short head chain.

by:Leren

 


is.gd/Leren_567_BX1

 

by: Toni

 
 
Very nice and easy.

 

by: Susan

 
 
30 min of fun!

 

by: BP

Add to this thread
 
Quick and relaxing.

by:Leren

 


is.gd/Leren_567_B2

 

by: Toni

 
 
Here I needed a short head chain and a UR argument.

 

by: BP

 
 
Great puzzle. CE, B setti power and patience does ist. No chain needed, instead I used something I'd call a hidden naked pair in a box. Thank you, Leren! BTW: Is ist possible we had this pattern before in one of your early B str8ts?

 

by: Flo

 
 
could you explain b-setti power in more detail?

 

by: BP

 
 
@Flo: B setti power depends on the following fact:

If a digit is missing from a row/col it must be missing from a box intersecting with that row/col. And vice versa: If a digit is missing from a box it must be missing from a row AND a col intersecting with that box.

Some examples: If a digit x is missing from row A it must be missing from box 1 or box 2 or box 3. If x is missing from A and C ist must be missing from two of the boxes 1,2,3.
Vice versa: If a digit x is missing from box1 it must be missing from A or B or C AND from col 1 or 2 or 3. If x is missing from boxes 1 and 2 it must be missing from two of the rows A,B,C AND once from col 1 or 2 or 3 and once from col 4 or 5 or 6.

In this puzzle (B2) I used B setti power in a more complicated way at one point to prove that 7 in E as follows:
From the beginning it's clear that DF5=67, E46=34 and 6 and 7 have to be in all cols except maybe for col7. So: If 7 not in E then 6 not in E then 6 and 7 are missing from E and col7, but have to be present in all other rows and cols. But then by B setti power 6 and 7 must both be missing from box6 which is not possible. (Note that this argument would not work if 6 and 7 might be missing from more rows and cols.)

Hope that helped.

 

by: Flo

Add to this thread
 
Ah. this is really a powerful tool. thanks for the detailed explanation!

by:Leren

 


is.gd/Leren_567_B1

 

by: Toni

 
 
Pretty and pretty easy

 

by: witch

 
 
same as Tony - fun

 

by: Susan

Add to this thread
 
Great one, nice and easy

by:Leren

 


is.gd/Leren_567_X

 

by: Toni

 
 
Chainless fun, but hard work. Exactly the way I like it - thanks again, Leren!

 

by: pets

 
 
What an amazing beauty! I do agree with Toni: Hard work but solves perfectly step by step. Thank you, Leren!

 

by: Andy B.

 
 
great puzzle - thanks !!!

 

by: BP

Add to this thread
 
Like Toni and pets. Fun!

by:Jens

 
Discussion of Andrew's Extreme Str8ts Puzzle, Quarantine Edition #199, May 2 - May 3

 

by: Miss P

 
 
From absolutely impossible ones to a very simple one - nice for a change, though. 5 mins.

 

by: dennis

 
 
a sweet fast one. many thanks. 8m.

 

by: jgrab

 
 
Yes, easy. 6 min.

 

by: Hel

 
 
13' w/c

 

by: KDN

 
 
w/c nice one

 

by: ThomasF

 
 
9' w/c pure fun

 

by: ilonaellen

Add to this thread
 
singles singles singles 15min

by:Jens

 
Discussion of Andrew's Extreme Str8ts Puzzle, Weekly Edition #567, May 2 - May 8

 

by: Jens

 
 
Some X-Wings and BCA 3.

 

by: hp

 
 
Only CE

 

by: Andrejs

Add to this thread
 
I always try to use the Setti rule and the BCA which are based on strictly logical considerations.
In this time at some stage I found that at least one column does not contain 3. So at least one row also does not contain 3. Rows E and G had to be checked because in other rows this number was sure digit. Starting with row G I get a contradiction. Thus row E definitely does not contain 3. This conclusion led to complete solution of the puzzle.



Article created on 27-June-2010.
This page was last modified on 16-March-2020.
All puzzles on this site are trademarked and patented and cannot be reproduced without permission.
Copyright Syndicated Puzzles Inc, 2010-2020

Boast or Rant!
Tell everyone if you solved this puzzle, how long it took or if you gave up.
Name or handle:

Comment,
including time to solve (or not :)


For questions or discussion, please use the main comment form.
  • 27 min - very nice
       - SBear - 3 hours ago
  • 23 min: took me ages to see the obvious
       - JimKnopf - 7 hours ago
  • 28 min - nice one
       - relijo - 2 days ago
  • 15 min - nice one, no guessing, just settis and CE
       - Susan - 3 days ago
  • 49', very nice
       - chris - 3 days ago
  • 14 min
       - humpti dumpti - 4 days ago
  • 18' with 1 guess. Skipped settis.
       - ttbass - 4 days ago
  • 25 2. Att. Fine....
       - Kmk - 4 days ago
  • about 15 min
       - Loser - 4 days ago
  • 26 min on 2nd try, without guess.
       - schnabelsau - 4 days ago
  • 40 - tough sledding for me
       - alopex - 4 days ago
  • PS. Have the boasts been disabled on purpose on the 'more extreme straits' page, or is it a bug?
       - martijn - 4 days ago
  • 15:40, no decisions needed. Nice!
       - martijn - 4 days ago
  • 30 Minutes lucky guess on A9 (1 or 4) was the key
       - Joe Reitzl - 4 days ago
  • 13' - no special tools, just uncommon logic
       - Arjan - 4 days ago
  • It needs a guess to solve it
       - Q - 4 days ago
  • nice, straightforward
       - easydoesit - 4 days ago
  • 38', perfect level, as far as i can see only one "decision" to make on D4 6/7
       - flowermount - 4 days ago
  • 18:20 Second attempt.
       - Mike - 4 days ago
  • 16 min; second try
       - cKay - 4 days ago
  • 11min, very nice, discovered unknown tool to detect E2, I name it the "the fatal"
       - fred - 4 days ago
  • 18 min
       - Chrissie - 4 days ago
  • 12' unusual, surprising
       - Richard - 4 days ago
  • Close to 2 hours. Kept making mistakes.
       - puzzled - 4 days ago
  • Nice one
       - mparmen - 5 days ago
  • 24' mts - CE and 1 setti (not really needed)
       - guilhas_ms - 5 days ago
  • 30 min, very nice one
       - Boerny - 5 days ago
  • 45' quite distracted,obv.
       - selecti - 5 days ago
  • 26' Not even settis needed. Compensation for last week?
       - Aubinger - 5 days ago
  • loved it
       - Hildi - 5 days ago