## hard minimal 8 clues JSWX examples

For fans of Killer Sudoku, Samurai Sudoku and other variants

### hard minimal 8 clues JSWX examples

Yes, my first 8 clues example. It took some preparation but the result has a nice form too.
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`#1/WX/B4,JS...........3...2......4..............5.....9..............7......8...1...........111111223441112233444222233444525533664555733665585777668888777668899977688999999`

Can you give the SE rating for jigsawexplainer?(SiSeSuSo estimates this around 7.5)

solution:
Hidden Text: Show
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`761492583913586247582743916346918752257361498894235671635174829478629135129857364111111557221115577222555577222353377662333877663343888664444888664499988644999999`

hints found by SiSeSuSo:
Hidden Text: Show
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`(UVW)XYZ-Wing  | TUVWXYZ Wing (-4)W2r4 => (-4)r4c6 | TUVWXYZ Wing (-7)W3r6 => (-7)r6c4`
Last edited by urhegyi on Mon Mar 08, 2021 1:27 am, edited 1 time in total.
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

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`...........3...2......4..............5.....9..............7......8...1........... 111111223441112233444222233444525533664555733665585777668888777668899977688999999 JSWX  8 ED=7.2/2.9/2.6`

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`Difficulty rating: 7.2This Windoku Jigsaw can be solved using the following logical methods:70 x Hidden Single (1.0-1.5)1 x Direct Claiming (1.9)1 x Direct Hidden Pair (2.0)1 x Direct Hidden Triplet (2.5)23 x Cage Pointing (2.6)36 x Claiming (2.8)44 x Generalized Intersection (2.9)4 x Hidden Pair (3.4)1 x Forcing Chain (7.2)`
1to9only

Posts: 3448
Joined: 04 April 2018

### Re: hard minimal 8 clues JSWX examples

This JSWX layout is rather good at producing 8-clues:
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`...............2...8.............7.........9..........6....4...........51........ JSWX ED=2.9/1.5/1.5..........1..8..4....................5.....9....................7..2..3.......... JSWX ED=2.9/2.3/2.3........3...5.......27.....................................48.......9...1........ JSWX ED=4.2/2.9/2.6..........1.....4.............9.8...............2.5.............7.....3.......... JSWX ED=7.7/2.3/2.3....9.....1.....4...................2.......8...................7.....3.....5.... JSWX ED=7.9/2.3/2.3.....................7.3......9.8...............2.5......1.4..................... JSWX ED=8.1/8.1/2.9....9........8.......7.3.................................1.4.......2........5.... JSWX ED=8.8/8.8/2.67..........3.......8....9...............................5....2.......1..........4 JSWX ED=8.9/8.9/2.6111111223441112233444222233444525533664555733665585777668888777668899977688999999`

Same solution grid: Show
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`761492583913586247582743916346918752257361498894235671635174829478629135129857364`
1to9only

Posts: 3448
Joined: 04 April 2018

### Re: hard minimal 8 clues JSWX examples

It's most of all the number 6 which is missing. Except for your first example where the number three is missing. All the other numbers occur only once.
A few easy ones for the p&p solvers:
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`.............8.................1.....57...49.....3.................2...........................................918.....7...4.....235..............................7.......3....8.......................5.....9.......................2....1.......4...........3...2.....................57...49.....................8...1.....................1.....4...................25.....98...................7.....3.........................................1....257...498....3.........................................1..8..4....................5.....9....................7..2..3............1...5......8........................7...4........................2......9...3................................9.8.....73.14.....2.5..............................`

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`111111223441112233444222233444525533664555733665585777668888777668899977688999999`
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

I found one with each number occuring only once, so 9 clues. After removing the 6 at R5C5 I got a 8 clues JSWX and backtracking confirms 1 solution, so it's valid, but I have no idea of the rating. It must be hard.
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`#1/WX/B4,JS....9......3...2......4...................................7......8...1......5....111111223441112233444222233444525533664555733665585777668888777668899977688999999`
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

Code: Select all
`....9......3...2......4...................................7......8...1......5.... 111111223441112233444222233444525533664555733665585777668888777668899977688999999 JSWX  8 ED=9.1/9.1/2.6`

urhegyi wrote:It's most of all the number 6 which is missing. Except for your first example where the number three is missing. All the other numbers occur only once.

This is probably just a coincidence! I've generated a few others where the 6 appears more often.

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`........3...58.......7.....................................4.......29...1........ JSWX  8 ED=2.8/1.2/1.27.......3....8.......................5.....9.......................2....1.......4 JSWX  8 ED=2.8/2.3/2.3..........1..8..4....................5.....9....................7..2..3.......... JSWX  8 ED=2.9/2.3/2.3.......8....5............1.........................67..3..................9.....4 JSWX  8 ED=2.9/1.2/1.27....2....1.5.......................................................9.3....8....4 JSWX  8 ED=7.9/7.9/2.6..1................8....9........7.............4........5....2................3.. JSWX  8 ED=8.1/8.1/2.6....9..................3.........7..2.......8..4.........1..................5.... JSWX  8 ED=8.1/7.9/2.9.........................1..4.....52.........89.....7..3......................... JSWX  8 ED=9.4/9.4/2.6111111223441112233444222233444525533664555733665585777668888777668899977688999999761492583913586247582743916346918752257361498894235671635174829478629135129857364`

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`....................5.4..8....9........3............6.......2.....7.............. JSWX  8 ED=8.8/7.7/2.6111111223441112233444222233444525533664555733665585777668888777668899977688999999678495123983127546125643987347982615516378492294531768731864259462759831859216374`

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`.............8........5...............1.................6....3.......4........92. JSWX  8 ED=2.9/1.9/1.9.......8...............9....5.7...6...1..4.........2............................. JSWX  8 ED=7.1/1.7/1.7....................31.97...............................64.58.................... JSWX  8 ED=10.0/10.0/2.8111111223441112233444222233444525533664555733665585777668888777668899977688999999124573689749682351683159742952748163361924578875396214296415837518237496437861925`

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`5............................9......1........3.......4..2.....67................. JSWX  8 ED=2.8/1.2/1.2..................23.5.........4.................8.........7.16.................. JSWX  8 ED=7.7/2.8/2.8....6.....4.....7...................1.......3...................5.....8.....2.... JSWX  8 ED=7.9/2.3/2.3...7.........3.............8.........2.....6.........4.............1.........5... JSWX  8 ED=9.4/9.4/2.6111111223441112233444222233444525533664555733665585777668888777668899977688999999594761238648239175231578649879643521125894763367182954982457316753916482416325897`

Some solution grids:

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`723541896436892157891756432652439781187623549945168273268375914579214368314987625678915324184327596325694187497182635536478912219543768743869251962751843851236479284765913643918572915273648378641295592384761167539824839427156721856439456192387162594387927386451384157926756928134431762598895473612673215849518649273249831765824617539149532768537869142962143857758924613316795284295486371683271495471358926842793651921654378653871924174925863368142795597316482416287539785439216239568147854921736246735198731896245695243871178654923329167584567489312983512467412378659762589134824136957139754826456823719917462583385941672641275398573698241298317465938576142782143659146952783253784916619238574475621398321895467594367821867419235759312648198645237642738195835194762267859314413286579586973421374521986921467853672315984124987536985634127437128695596472318813549762749263851368751249251896473243691875935874162871265934564937281182543697796158423458326719627419358319782546861935472312476598475892316296317845548261937739524681624189753987653124153748269968542713483716259712953486356481972279368541145237698637895124591624837824179365159624873293875461874163295365297184481359627726438519538916742617542938942781356925468137657132849138947652742653918819725463364871295271594386493286571586319724239517684194683752687254193453198267762439518815746329346925871528371946971862435364927815245816793817395246596241387783564921129758634658439172931672458472183569651429738218735946739648215845213679976851423324987561587164392463592187192376854958726341281345679346971285175284936639158724427613598513897462794562813862439157111111223441112233444222233444525533664555733665585777668888777668899977688999999`
1to9only

Posts: 3448
Joined: 04 April 2018

### Re: hard minimal 8 clues JSWX examples

New layout with 8 clues example. Needs forcing nets. So SE 9+?
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`#1/WX/B4,JS.....................9.3............15.....74............6.8.....................111155666211155566221157566222757566222777888334747888334749988334449998333449999`

analyze log:
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`Eliminated candidates per Method and per SudokuMethod   \  Sudoku |   SER |     1                   |-------|------Not counted elims  |     0 |    77Naked Singles      |   0.1 |    36Hidden Singles     |   0.2 |   123Naked Pair    [2]  |     3 |     6Naked Triple  [3]  |   3.6 |    16Hidden Quad   [5]  |   5.4 |    12Pointing/Claiming  |   2.8 |   156Locked Singles[3]  |   2.9 |    16Locked Singles[4]  |     3 |    26Locked Singles[5]  |   3.1 |     5XY-chain      [4]  |   4.6 |     1XY-chain      [5]  |   5.1 |     1Forcing Nets  [4]  |   9.4 |     4Forcing Nets  [5]  |   9.5 |    10                   |-------|------Eliminated Cand's  |   489 |   489Sum(SER * Cand's)  | 887.6 | 887.6Initial Candidates :   489Maximum SER rating :   9.5 <- Approach Labour rating      : 887.6 <- Experimental ratingGuesses (BF/BT;FN) :   986Time needed        : 00:00:08.920`

solution:
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`761492583832546791278953146946135827153829674529764318314678952485317269697281435111155666211155566221157566222757566222777888334747888334749988334449998333449999`
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

If the last posted example was to hard try thisone:
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`#1/WX/B4,JS..........3.....9...................18.....76...................4.....2..........111155222111555222115554422336654442336666644833376644883377799888777999888779999`

solution:
Hidden Text: Show
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`761492583538167492924583167497638251182954376653721849816275934349816725275349618111155222111555222115554422336654442336666644833376644883377799888777999888779999`
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

Most symmetrical 8 clues JSWX possible!

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`#1/WX/B4,JS..............................219......7.4......638..............................111133344221133344221133444222135544225555588665579888666779988667779988667779999`
urhegyi

Posts: 539
Joined: 13 April 2020

### Re: hard minimal 8 clues JSWX examples

urhegyi wrote:Most symmetrical 8 clues JSWX possible!
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`#1/WX/B4,JS..............................219......7.4......638..............................111133344221133344221133444222135544225555588665579888666779988667779988667779999`
very nice layout / puzzle

Hajime

Posts: 732
Joined: 20 April 2018
Location: Netherlands