Puzzle Corner

[Black Hole]

A worthy challenge:

   ———————————————————————
  |   |   |   |   |   | O |
  |———|———|———|———|———|———|
  |   |   |   |   | O | O |
  |———|———|———|———|———|———|
  |   |   |   | X |   |   |
  |———|———|———|———|———|———|
  |   |   | O |   |   |   |
  |———|———|———|———|———|———|
  |   | X |   |   |   |   |
  |———|———|———|———|———|———|
  | X |   |   |   |   |   |
   ———————————————————————

 

[prpr]

A worthy challenge

Less than 2 minutes, and that was doing it in a text editor. Would have been quicker with a piece of paper.

 

[Black Hole]

Sure, but about as hard as they get. I counted four applications of "advanced" logic, but by doing that analysis I slow myself down.

 

[EEPhil]

Took me longer than normal. Nearly got stuck half way through. Not sure what you mean by advanced logic. If it is of the form “if I put an X there that’ll mean three 0 in a row, therefore it’s a 0”, I can only remember doing that twice. Difficult, but not that difficult.

 

[Black Hole]

Here's the GCHQ Christmas Challenge (for children!):

 

[Black Hole]

Another, apparently as hard as they come (and, with typical perverseness, only rated 2 stars when easy ones get 3):

   ———————————————————————
  |   |   |   |   |   | O |
  |———|———|———|———|———|———|
  | X |   |   |   | X |   |
  |———|———|———|———|———|———|
  |   |   |   | O |   |   |
  |———|———|———|———|———|———|
  |   | O | O |   |   |   |
  |———|———|———|———|———|———|
  |   |   |   |   |   | O |
  |———|———|———|———|———|———|
  |   |   | O |   | X |   |
   ———————————————————————

 

[EEPhil]

I’m a bit out of condition with these, usually only doing the Saturday one. I did find this the hardest one I’ve done in a while. Worth more than three stars. Two, they’re taking the p.

 

[Black Hole]

It's the three star which take the pee (Saturday is always one of those!). I really don't get it – as I said above, the star system is perverse.

 

[EEPhil]

as I said above, the star system is perverse.

More likely inverse

 

[Black Hole]

Just for the record (for the bystanders): the stars are "difficulty rating" not "easiness rating"!

 

[Black Hole]

To reiterate the point, today's "3 star"!:

 

[EEPhil]

Less than one minute for the three star. More than four minutes for the two star.

 

[prpr]

35" (paper) and 2'15" (text editor - much slower) respectively.

 

[Black Hole]

I timed myself on today's "3 star": 21" (this isn't a race, it's a comment on the star rating system).

 

[EEPhil]

That was very easy. (39”, but who’s counting). Hard to compare with ones you've transcribed as I have to write them out first - and maybe working them out as I do so. Today’s was from the paper itself. The difficulty rating is just made up!

 

[Black Hole]

 

[EEPhil]

I didn’t time it, but fairly easy. Perhaps 2 stars okay for this one.

 

[Black Hole]

fairly easy

Really? So far as I can see, solution relies on getting the bottom left corner, which itself relies on getting the bottom right corner. 3 star in my book (2 star being one inference, 1 star requiring no inference at all).

 

[prpr]

Seems unworthy of 3 to me.
B2, C3, D3 are trivial, F6 leads to A6 and then fill the rest in.

 

[Black Hole]

B2, C3, D3 are trivial, F6 leads to A6 and then fill the rest in.

Your logic agrees with mine; our rating just differs on where to set the threshold (one or two inferences). I don't recall seeing a Kurosu which requires more than three inferences, so making this one 2-star offers very little step up to 3-star (unlike the Mail's "difficulty" rating, which seems to assign 3 stars when the grid can be solved by inspection with no inferences at all).