Star Battle by John Bulten

Star Battle by John Bulten


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

Theme: UWU

Author/Opus: This is the 73rd puzzle from our contributing puzzlemaster John Bulten.

Rules: Standard Star Battle rules. Two stars per row, column, and region.

Difficulty: 1.5 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:00, Expert = 4:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other classic Star Battles and this link for Star Battle variations. If you are new to this puzzle type, here are our easiest Star Battles to get started on. More Star Battle puzzles can be found in The Art of Puzzles, in the books Star Battle by JinHoo Ahn and Star Battle 2 by JinHoo Ahn and Murat Can Tonta, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

  • Avatar photo Chandrachud says:

    Good one … deductions flowed.

  • Avatar photo Deanna says:

    Any reason for shifting away from for Star Battles? I think their online solving interface is superior to what Penpa has going on, at least in what I saw with this one.

    • Avatar photo drsudoku says:

      Deanna: We publish about 20 styles of puzzles and 100’s of one-off variations of them. Penpa gives us a starting point for 99.5% of our puzzles to be on the web where is much farther from being so customizable to let us post web versions of all our puzzles, with solving checks enabled and with proper author/title/attribution associated on pages we host.

      That said, we recognize that there are some styles where individual tools (, F-Sudoku, other things our fans have added into the comments of posts) may offer better digital experiences for a given genre. My own example is loving Nikoli’s Akari interface, and I refuse to publish paper puzzle versions of that style given how naturally it solved on web and phone.

      We aim to encourage further development of Penpa to have these benefits come in. Within the UI of Penpa (but not in the default composite solving interface) is already a way with Border: ON to put in some notes on corners and edges and you’ll probably see me do this in our solving videos this week. But we aim to improve; when penpa-edit is updated our site will get the benefits for all puzzles we’ve posted including our back catalog as we add these as well. That is our meaning of being in “beta mode” — tell us what is less than ideal and we’ll try to make it better. (Right now this means a lot of open-source development by Swaroop, but we plan to encourage/fund more development.)

  • Avatar photo Bryce Herdt says:

    I agree. The helper dots take a load off.

    As for the question, I don’t know; wild speculation follows. My suspicion is they are, on a trial basis, putting *everything* onto Penpa. All the puzzles last week were variants (but with the theme that they also solve as the vanilla types). That means that on, the answer checker won’t recognize the intended solution; Penpa allows setting an arbitrary solution. (And an arbitrary puzzle type, rather than needing to code up an interface for even a vanilla Cross the Sreams.)

    But I skipped a step: why does GMP need to pick a lane in the first place? I might guess they see themselves as a company, one that needs policies; I might further guess the policy of a single interface site is aimed at reducing how many things new visitors need to learn.

    Then again, I could easily be wrong about lots of this. I think GMP’s switched at least three times, and I doubt those can all be motivated by knowing it needed to change.

  • Avatar photo Bryce Herdt says:

    Er. I replied below, but I thought I was replying to you. I clicked your comment’s Reply text several times trying to be sure.

  • Avatar photo Bryce Herdt says:

    That didn’t work either? Oh well.

    • Avatar photo drsudoku says:

      Replies on our site haven’t threaded right in a few months from the web side (they work from within my wordpress tools) — not sure how to fix, but I appreciate your message upthread to Deanna.

  • Avatar photo Swaroop says:

    I can answer part of your question. The dot feature is work in progress and should be available soon.

  • Avatar photo Deanna says:

    Thanks for the replies!

    Threading is weird, indeed, so I’ll just reply here: Yes, the dot feature is a huge benefit to Thanks to you guys using it before, I went through and solved just about every single star battle that people have done on, and the earlier ones are definitely more painful because dots don’t work, so I had to choose between either mentally remembering where stuff might be, or doing things like putting in two stars in a two-star possible area, etc. I’m sure everyone’s gone through that. I’m glad to hear you’re working on it for penpa though. I also liked the gmpuzzles ones best though just because I got a better idea of how much time to expect to spend on those (even the interface where people rate the difficulty isn’t entirely consistent. But either way I enjoyed diving into a ton of them).

    Also, I haven’t been able to log in here for around a year now for the answer checker and favoriting puzzles, but I wasn’t even sure who to ask and I only do a subset of the puzzle types, and having the solve-online tools means that in most cases I know when I’ve solved it anyway, so it isn’t that necessary to check anymore. My Griddle account definitely works, so not sure what’s up.

    • Avatar photo drsudoku says:

      The login widget has had security issues (as it is externally hosted) for a lot of users and we don’t have a recommended browser to get around it consistently. I’ve contracted to have it updated and hope it is fixed by end of quarter. I had wanted to deprecate it but enough people shared feedback they like clicking on puzzles as done to track their progress. My goal as Penpa evolves and whether it is our digital interface or something else, is that we have a database of all our puzzles that you can navigate by style, with user IDs alongside the tool so you can store your solving history more actively with the site. We don’t have a full time engineer on-board now though so this will come slowly but we’ll probably scale the team soon.

  • Avatar photo skynet says:


  • Avatar photo Rajesh Kumar says:

    3.09 Mins to solve this one. This is a nice puzzle.

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