### Dr. Sudoku Prescribes #30 – Consecutive Sudoku

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Theme: Jekyll and Hyde – digits but no bars up top, bars but no digits down below. Master both sides to solve this puzzle.

Rules: Standard Consecutive Sudoku rules.

Answer String: Enter the 1st column from top to bottom, followed by a comma, followed by the 9th column from top to bottom.

Time Standard: Consecutive Sudoku Master = 4:30, Expert = 13:30, Novice = 45:00

Solution: PDF and solving video.

• Oof. I feel like I am missing a constraint. I should be able to logic the bottom left to quadrants, but I still have multiple ways they can fit without breaking. Do I really need to try each combination and then solve the puzzle to see if it breaks at the end?

• drsudoku says:

Quite likely some “nonconsecutive” constraint is not yet in your view. There is no need to try any guesses to get through this, but there is a pretty narrow path at the start.

• Jack Bross says:

Don’t take that “master both sides” too literally 😀

• Tom Collyer says:

I definitely enjoyed the break-in, and I must say this puzzle definitely felt more like a non-consecutive puzzle as opposed to a consecutive. It reminded me of a recent discussion about trying to make non-consecutive puzzles by hand vs. getting a computer to give you a solution grid and then carefully selecting a subset of givens. I suspect in puzzles like this the balance is swayed enough to give the author a fighting chance of turning a cool idea into a valid puzzle.

(Just the 12 blanks cells at the point I got the codes this time. I am concerned about the fact I’m solving these puzzles slightly differently from everyone else!)

• drsudoku says:

Glad you liked it – definitely built the framework of the bottom around the break-in, thinking it might still give a “non-consecutive” feel to the whole thing even though it has bars.

On the entry rows, “everyone else” is probably just me with my finger on the scale, since I make the final call on the entry rows. Since this isn’t a competition, I haven’t made it one of the high priorities of my testers, and I bet I’m commonly wrong for some people.

• skynet says:

36 mins 1 s

Motris maybe you should make me test solve the puzzles so that you can get exact novice times:( . 🙂
nowhere near the expert time..
Clueless at the start of the puzzle …was going from box to box like a destitute to get atleast one number…
In the end beautifully hidden like a treasure the 4 and 6 ,5th column in the 8th box…Ohhhh it took me 24 mins to write the first number which was in the 8th box…
Difficulty level on a scale of 10 : do i need to say?its obvious
Fun level : 10!!!
Hardest of the week….4 : 30?!!!! even for a master is stunning?i wonder who is your test solver motris? ..He must be very good!

• drsudoku says:

I’m glad you liked the puzzle for its challenge.

I routinely have at least five test solvers at the moment. And some combination of my instincts and their times is how I determine the cutoffs, particularly on sudoku puzzles.

On this puzzle, getting started is the big thing. The more experienced solvers have an easier time seeing how little there is going on anywhere in the puzzle except in the middle columns. So if they find the path sooner — cutting out most of those 24 minutes — they can actually finish in about 5 minutes.

Scared the master times this week but these may be my strongest types in both sudoku and non. Would be curious to see what type of markup you use on paper for the more extreme puzzles when the ‘need’ to guess/bifurcate comes along.

• drsudoku says:

Having never found a color pencil that erases well, I generally write a first number in a box, and then all subsequent numbers with an underline. It is easy enough to erase all of them if it proves wrong, but sometimes the small notes get corrupted so it tends to be a big erasure when it happens. I’m sure there are better systems, but I lost interest in discovering them around the time I lost interest in Sudoku competition in 2009 (Slovakia + Eugene).

• hagriddler says:

My break in revolved around the center cell and the 4’s and 6’s, was that intended ? I loved it !

• drsudoku says:

Yes, the center column with the 4/6 in box 8 is what is intended as the work-in, which can get you several cells including the center cell.

• hagriddler says:

After that it’s a pretty narrow path to the end, nice puzzle !

• Roland Voigt says:

I had no strong feelings about the other two consecutive sudokus, but this one was just brilliant. RV

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