Dr. Sudoku Prescribes #7 – Nurikabe

Nurikabe by Thomas Snyder


or solve online (using our beta test of Penpa-Edit tools)

Theme: Twin Islands

Rules: Standard Nurikabe rules.

Answer String: Enter the length in cells of each of the black segments (the unnumbered, connected “ocean”) from left to right for the marked rows, starting at the top. Separate each row’s entry from the next with a comma.

Time Standard: Nurikabe Master = 1:00, Expert = 3:00, Novice = 10:00

Solution: PDF

  • tamz29 says:

    I tried to enter the solution three times and have it come up as incorrect. Then I realised I was using my notation of http://roygbivpuzzles.wordpress.com/2012/10/14/light-read-1-inverting-the-nurikabe/ where black/white cells are inverted.

    • Andrew Brecher says:

      Now this is odd…I saw this 13-month-old link to “Light Read 1” today, for the first time, randomly going through some old puzzles on this web site. Then I click through and find “Light Read 2” was posted just a few hours ago…!

  • Ravi says:

    Nice, quick and easy.
    Took ~2 min to solve and took 8 min to enter answer key.
    First entered in incorrect format, later gave correct format but still showed ‘Incorrect’, after few more attempts it asked for Griddle credentials.

    If possible please implement the feature to pop-up small window for asking the user to enter Griddle credentials when clicked on ‘Solved’ button. (I remember when I first accessed this site this feature was present)


    • Avatar photo drsudoku says:

      There will be some major updates to the Solved button soon that fix a lot of issues like this.

      I have changed the wording of the answer entry so that parity (island versus ocean) doesn’t matter. I’d love to have it so that “commas” don’t matter too but that will also be a future update. Thanks for your patience!

    • dmillar says:

      Hey Ravi: As the good doctor already mentioned, updates for this feature are planned. I’m planning on replacing the pop-up dialog with a styled box similar to the login/register box that will require being signed in first.

  • Allen Kong says:

    Good introductory puzzle to those unfamiliar to this type. 1’15” here. Looks like you tried hard to fit a 2-2 clue duet somewhere. Still a nice puzzle. Thanks.

    I still don’t know how you have all this time to create/solve puzzles and still work a full-time job. I can barely find time to solve puzzles in between seeing patients and operating, let alone taking care of two little munchkins at home.

    Keep up the good work. Great site so far.


    • Farfarawayfan says:

      “I still don’t know how you have all this time to create/solve puzzles and still work a full-time job.”

      There is a genius inside of this matter..

  • muhorka says:

    Nice theme, I really enjoy it (time 1:00)

  • Allison says:

    Ok, I think this question probably disqualifies me from participating, but where do you enter your answer?

    • Avatar photo drsudoku says:

      The button requires JavaScript so if you don’t see it at the bottom of the post it may not work with your current browser settings. I’ll try to put up a general info/troubleshooting page this week that can help

  • skynet says:

    How to start doing this puzzle.I read the Nurikabe rules and info but still clueless on how to start……….

  • Eric Berlin says:

    I can confirm that this was an excellent introduction to Nurikabe, as it was the first one I ever solved. I’ll pass on saying how long it took me, though…

  • skynet says:

    Thnks Dude that was a cute little introductory presentation..was waiting all day to see a helpful comment..now you have provided me one..will start doing this puzzle now

  • skynet says:

    13 mins 33 sec to solve after seeing that intro post !!!!delighted thnks affpuzz

  • Rishi Puri says:

    Though I consider myself a novice when it comes to puzzles in general, I think I’m happy with my 3’12” on this one. 🙂

  • 57 seconds. Cool. Just in time. 😛

  • ksun48 says:



  • Carl W says:

    I’m having trouble having my answer accepted. I believe my solution is correct and that I’m computing the correct answer string, (I even tried reversing the parity), but the applet keeps saying “Incorrect”.

    I don’t know if anyone is reading new comments to old puzzles like this, so I’ll also email Dr. Sudoku directly. (For what it’s worth, the answer entry for several similarly-old puzzles has worked fine for me.)

    • Carl W says:

      My mistake. I was letting one “island” illegally contain two numbers, (as if this were more like a Fillomino). So following the correct puzzle instructions does lead to an aswer string that is accepted.

      Thanks for setting me straight, Thomas.

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