The New Sudoku Players' Forum

by **champagne** » Sat Nov 15, 2025 8:17 am

In my attempt to split puzzles in 'TH threat' and 'no TH', I had to look at the solution grid 452307986

in the TH file, I had these 3 puzzles assumed to have a 'TH threat' and rating skfr 11.0 and more
.23..67...56....2.7........2....7.5.....1.....3......73..9625715....3.6...28..934
.23..67...56....2.7..2.....2....7.5.....1.....3..2...73....25715....3.6...28..934
.23..67...56....2.7..2.....2....7.5.....1.....3..2...73....25715...43.6...28...3.

the second and the third have the quick signal of a possible TH
They don't have the TH, but I think that a nice path can come here
Start PM for the first one

Code: Select all: 1489 2 3 |145 4589 6 |7 1489 589 1489 5 6 |1347 34789 1489 |1348 2 389 7 1489 1489 |12345 234589 14589 |13468 1489 35689 ------------------------------------------------------- 2 14689 1489 |346 3489 7 |13468 5 3689 4689 46789 45789 |23456 1 4589 |23468 489 23689 14689 3 14589 |2456 24589 4589 |12468 1489 7 ------------------------------------------------------- 3 48 48 |9 6 2 |5 7 1 5 179 179 |147 47 3 |28 6 28 16 167 2 |8 57 15 |9 3 4

by **totuan** » Sat Nov 15, 2025 10:50 am

champagne wrote:In my attempt to split puzzles in 'TH threat' and 'no TH', I had to look at the solution grid 452307986
in the TH file, I had these 3 puzzles assumed to have a 'TH threat' and rating skfr 11.0 and more
.23..67...56....2.7........2....7.5.....1.....3......73..9625715....3.6...28..934
.23..67...56....2.7..2.....2....7.5.....1.....3..2...73....25715....3.6...28..934
.23..67...56....2.7..2.....2....7.5.....1.....3..2...73....25715...43.6...28...3.

I don’t see TH but exocet. Brief some moves at start for the first one:

Code: Select all: *---------------------------------------------------------------------------------* |B’1489 2 3 | 145 4589 6 | 7 B1489 589 | | *1489 5 6 | 1347 34789 A1489 |T’1348 2 T’389 | | 7 T1489 T1489 | 12345 A’234589 14589 | 6-1348 *1489 56-389 | |--------------------------+--------------------------+---------------------------| | 2 14689 1489 | 346 3489 7 | 13468 5 3689 | | 489-6 46789 45789 | 23456 1 4589 | 23468 *489 23689 | | 1489-6 3 14589 | 2456 24589 4589 | 12468 *1489 7 | |--------------------------+--------------------------+---------------------------| | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 179 | 147 47 3 | 28 6 28 | | 16 167 2 | 8 57 15 | 9 3 4 | *---------------------------------------------------------------------------------*

1.Exocet(1489) T-A-B
2.Almost exocet(13489) T’-A’-B’: if T’<>3 => exocet(1489) T’-A’-B’
3.By (1489)r3c8 and exocet(1489) T-A-B => in B3 T’ must be 3’s
(1),(2),(3) => r3c79<>13489

After that with the same way => r56c1<>6 then the puzzle downgrade to ER-9.3
Thanks for the puzzle!
totuan

by **champagne** » Sat Nov 15, 2025 12:26 pm

Hi totuan,

agreed that these are likely JEs.

On my side for the first puzzle,

easy to show that digit '1' can't be in the base, requiring both targets
easy to show then that digit '9' is in the base due to the UR 48

but I don't have the nice path to go to the end.

by **champagne** » Sun Nov 16, 2025 8:16 am

my final proposal for this puzzle

Code: Select all: .23..67...56....2.7........2....7.5.....1.....3......73..9625715....3.6...28..934 1489 2 3 |145 4589 6 |7 1489t 589 1489 5 6 |1347 34789 1489t |1348 2 389 7 1489b 1489b |12345 234589 14589 |13468 1489 35689 ------------------------------------------------------- 2 14689 1489 |346 3489 7 |13468 5 3689 4689 46789 45789 |23456 1 4589 |23468 489 23689 14689 3 14589 |2456 24589 4589 |12468 1489 7 ------------------------------------------------------- 3 48 48 |9 6 2 |5 7 1 5 179 179 |147 47 3 |28 6 28 16 167 2 |8 57 15 |9 3 4

JE r3c23;r1c8,r2c7
digit '1 in base hit both targets => not valid
then UR 49r3c23r7c23 => 9 in base r9c1=6

Code: Select all: 148 2 3 |145 458 6 |7 489t 589 148 5 6 |1347 34789 489t |1348 2 38 7 489b 489b |12345 23458 1458 |13468 148 3568 ------------------------------------------------------- 2 14689 1489 |346 3489 7 |13468 5 3689 489 46789 45789 |23456 1 4589 |23468 489 23689 489 3 14589 |2456 24589 4589 |12468 1489 7 ------------------------------------------------------- 3 48 48 |9 6 2 |5 7 1 5 179 179 |147 47 3 |28 6 28 6 17 2 |8 57 15 |9 3 4

then, derived from totuan path
1;4;8 in r2c79 => same in r1c1 must be 3 in r2c79
the, if 38 in r2c79
=> exocet 49 4r1c8,9r2c5
=> 8r1c1 now invalid pattern 457 r1279c5
r2c9=3 r2c7 14

Code: Select all: 148 2 3 |145 458 6 |7 489t 589 148 5 6 |147 4789 489t |14 2 3 7 489b 489b |12345 23458 1458 |1468 148 568 ------------------------------------------------------- 2 14689 1489 |346 3489 7 |13468 5 689 489 46789 45789 |23456 1 4589 |23468 489 2689 489 3 14589 |2456 24589 4589 |12468 1489 7 ------------------------------------------------------- 3 48 48 |9 6 2 |5 7 1 5 179 179 |147 47 3 |28 6 28 6 17 2 |8 57 15 |9 3 4

then #8r1c2 same conflict
then #8r3c789 same conflict
now #8r1c1 the exocet base is 89
basics to the end

all high ratings in this solution grid ( 19 in the base rating >=105) seem to be variants of this exocet

by **Cenoman** » Sun Nov 16, 2025 8:44 pm

champagne wrote:easy to show that digit '1' can't be in the base, requiring both targets

champagne wrote:digit '1 in base hit both targets => not valid

Could you elaborate ?

My solution:
(Shortcuts used for JE: BD, NBD -> Base Digit, Non base digit; BC, TC -> Base Cell, Target Cell; MN -> Mirror Node)

Code: Select all: +--------------------------+---------------------------+-------------------------+ | 1489 2 3 | 145 4589 6 | 7 t1489 89-5 | | 1489 5 6 | 147-3 4789-3 t89-14 | 1348 2 389 | | 7 b1489 b1489 | 12345 234589 14589 | 13468 1489 35689 | +--------------------------+---------------------------+-------------------------+ | 2 14689 1489 | 346 3489 7 | 13468 5 3689 | | 4689 46789 45789 | 23456 1 4589 | 23468 489 23689 | 4 8 9 | 14689 3 14589 | 2456 24589 4589 | 12468 1489 7 | 1 4 8 9 +--------------------------+---------------------------+-------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 179 | 147 47 3 | 28 6 28 | | 16 167 2 | 8 57 15 | 9 3 4 | 1 +--------------------------+---------------------------+-------------------------+ x x x

JE(1489)r3c23, r1c8, r2c6
Eliminations: -5 r1c9 (NBD in MN/locked 7), -14 r2c6 (BD false in MN), -3 r2c45 (NBD in MN/locked 7); lcls, 2 placements

Code: Select all: +--------------------------+-------------------------+------------------------+ | a1489 2 3 | A45-1 B4589 6 | 7 1489 89 | | a1489 5 6 | 147 4789 89 | 1348 2 389 | | 7 b1489 b1489 | 23 23 c1489 | 6 1489 5 | +--------------------------+-------------------------+------------------------+ | 2 14689 1489 | 346 3489 7 | 1348 5 3689 | | 4689 46789 45789 | 23456 1 4589 | 2348 489 23689 | | 14689 3 14589 | 2456 24589 4589 | 1248 1489 7 | +--------------------------+-------------------------+------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 179 | D147 D47 3 | 28 6 28 | | 6-1 167 2 | 8 C57 d15 | 9 3 4 | +--------------------------+-------------------------+------------------------+

(1)r12c1 = r3c23 - r3c6 = r9c6 => -1 r9c1
(5)r1c4 = r1c5 - (5=7)r9c5 - (7=41)r8c45 => -1 r1c4; lcls, 3 placements

Code: Select all: +-------------------------+-----------------------+------------------------+ | 1489 2 3 | 45 589 6 | 7 t189-4 89 | | 1489 5 6 | 17 789 t89 | 1348 2 389 | | 7 b189-4 b189-4 | 23 23 1489 | 6 1489 5 | +-------------------------+-----------------------+------------------------+ | 2 14689 1489 | 34 389 7 | 1348 5 3689 | | 489 46789 45789 | 2345 1 4589 | 2348 489 23689 | | 1489 3 14589 | 6 2589 4589 | 1248 1489 7 | +-------------------------+-----------------------+------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 179 | 17 4 3 | 28 6 28 | | 6 17 2 | 8 57 15 | 9 3 4 | +-------------------------+-----------------------+------------------------+

JE(1489)r3c23, r1c8, r2c6
Eliminations: -4 r1c8 (BD false in MN) => 4 is false in BC: -4 r3c23; lcls

Note: at the resulting resolution state, assuming that 1 is a false base digit solves the puzzle: -1r2c23, -1r1c8, -1r2c4, (i.e. 1 false in BC, TC and MN); ste

Otherwise:

Code: Select all: +-------------------------+-----------------------+------------------------+ | 1489 2 3 | d45 589 6 | 7 189 89 | | E1489 5 6 | D17 789 89 |EA148-3 2 389 | | 7 189 189 | 23 23 Cc1489 | 6 B1489 5 | +-------------------------+-----------------------+------------------------+ | 2 14689 1489 | 34 389 7 | 1348 5 3689 | | f89 4689-7 f45789 | e2345 1 f4589 | 2348 f489 23689 | | 189 3 14589 | 6 2589 4589 | 1248 1489 7 | +-------------------------+-----------------------+------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 19-7 | 17 4 3 | 28 6 28 | | 6 a17 2 | 8 57 b15 | 9 3 4 | +-------------------------+-----------------------+------------------------+

(7=1)r9c2 - r9c6 = (1-4)r3c6 = (4-5)r1c4 = r5c4 - (5=4897)r5c1348 => -7 r5c2, r8c3
(4)r2c7 = r3c8 - (4=1)r3c6 - r2c4 = (14)r2c17 => -3 r2c7; lcls 2 placements

Code: Select all: +------------------------+----------------------+-----------------------+ | y148-9 2 3 | b45 a589 6 | 7 18-9 ea89 | | y1489 5 6 | 17 789 89 | 148 2 3 | | 7 z189 z189 | 23 23 D1489 | 6 E148-9 5 | +------------------------+----------------------+-----------------------+ | 2 14689 1489 | 34 389 7 | 1348 5 689 | | x89 4689 7 | c2345 1 4589 | c2348 wA489* d2689 | | 189 3 5 | 6 289 C489 | B1248 B1489 7 | +------------------------+----------------------+-----------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 19 | 17 4 3 | 28 6 e28 | | 6 17 2 | 8 57 15 | 9 3 4 | +------------------------+----------------------+-----------------------+

(9=85)r1c59 - r1c4 = (53-2)r5c47 = r5c9 - (2=89)r18c9 => -9 r1c18
Kraken cell (489)r5c8
(4)r5c8 - r6c78 = r6c6 - r3c6 = (4)r3c8
(8)r5c8 - (8=9)r5c1 - r12c1 = (9)r3c23
(9)r5c8
=> -9 r3c8; 1 placement

Code: Select all: +------------------------+----------------------+----------------------+ | c148 2 3 | 45 b58 6 | 7 c18 9 | | d1489 5 6 | 17 a789 a89 | e14-8 2 3 | | 7 189 189 | 23 23 B1489 | 6 A148 5 | +------------------------+----------------------+----------------------+ | 2 14689 1489 | 34 389 7 | 1348 5 68 | | 89 4689 7 | 2345 1 4589 | 2348 89-4 268 | | 189 3 5 | 6 289 C489 | D1248 D1489 7 | +------------------------+----------------------+----------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 19 | 17 4 3 | 28 6 28 | | 6 17 2 | 8 b57 15 | 9 3 4 | +------------------------+----------------------+----------------------+

(8=97)r2c56 - (7=58)r19c5 - (8=14)r1c18 - r2c1 = (4)r2c7 => -8 r2c7
(4)r3c8 = r3c6 - r6c6 = r6c78 => -4 r5c8; lclste

by **champagne** » Sun Nov 16, 2025 10:11 pm

Cenoman wrote:
champagne wrote:easy to show that digit '1' can't be in the base, requiring both targets

champagne wrote:digit '1 in base hit both targets => not valid

Could you elaborate ?

This is trivial logic.

We need 2 digits and each digit needs one target
If one digit true forces the 2 targets, then it can not be in the base (and not in the targets)

Unless I was wrong, '1' in the base => both targets are '1'

by **Cenoman** » Mon Nov 17, 2025 10:21 am

champagne wrote:Unless I was wrong, '1' in the base => both targets are '1'

Hi champagne,
Base cells are r3c2, r3c3. Target 1 cell is r1c8, target cell 2 is r2c6.
r2c6 cannot be 1 (because there is no 1 in its mirror node, r1c79). But let's put this aside.
You seem to come to your assertion

'1' in the base => both targets are '1'

at the very first move.

To me,'1' in the base means +1 r3c2|r3c3 <=> -1r12c1, -1r3c4678.
+1r3c2 forces +1r1c8 with the X-chain: (1)r1c8 = r1c4 - r8c4 = r8c3 - r4c3 = r4c7 => -1 r2c7, r6c8 (=> +1 r1c8)
Same for +1 r3c3 with the X-chain: (1)r1c8 = r1c4 - r8c4 = r8c2 - r4c2 = r4c7 => -1 r2c7, r6c8 (=> +1 r1c8)

Please, could you write explicitly the 'trivial logic' yielding +1r2c6 in the resulting PMs ?

Code: Select all: +--------------------------+-------------------------+------------------------+ | 489 2 3 | 45 589 6 | 7 1 589 | | 489 5 6 | 17 3789 1489 | 348 2 389 | | 7 1 489 | 2345 23589 4589 | 3468 489 35689 | +--------------------------+-------------------------+------------------------+ | 2 4689 1489 | 346 389 7 | 13468 5 3689 | | 4689 46789 45789 | 23456 1 4589 | 23468 489 23689 | | 14689 3 14589 | 2456 2589 489 | 12468 489 7 | +--------------------------+-------------------------+------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 79 179 | 17 4 3 | 28 6 28 | | 16 67 2 | 8 57 15 | 9 3 4 | +--------------------------+-------------------------+------------------------+ +--------------------------+-------------------------+------------------------+ | 489 2 3 | 45 589 6 | 7 1 589 | | 489 5 6 | 17 3789 1489 | 348 2 389 | | 7 489 1 | 2345 23589 4589 | 3468 489 35689 | +--------------------------+-------------------------+------------------------+ | 2 14689 489 | 346 389 7 | 13468 5 3689 | | 4689 46789 45789 | 23456 1 4589 | 23468 489 23689 | | 14689 3 4589 | 2456 2589 4589 | 12468 489 7 | +--------------------------+-------------------------+------------------------+ | 3 48 48 | 9 6 2 | 5 7 1 | | 5 179 79 | 17 4 3 | 28 6 28 | | 16 167 2 | 8 57 15 | 9 3 4 | +--------------------------+-------------------------+------------------------+

(Of course, brute force says that these have no solution. Hopefully, brute force is not what you call 'trivial logic' ?)
What do I miss ?

by **champagne** » Mon Nov 17, 2025 3:56 pm

Hi cenoman,

champagne wrote:Unless I was wrong, '1' in the base => both targets are '1'

Good to always keep room for error.
I was quite convinced that this was true,
How did this came; nothing new, but the situation as usual without the compendium

the '1' PM at the start with th 2 targets shown

Code: Select all: ... 1.. .t. ... 1.t 1.. .11 ... .. .11 ... 1.. ... .1. ... 1.1 ... 11. ... ... ..1 .11 1.. ... 11. ..1 ...

if the 2 targets are noty assigned, we are quickly here with an invalid pattern

Code: Select all: ... 1.. ... ... ... 1.. .11 ... .. .11 ... ... ... .1. ... ... ... .1. ... ... ..1 .11 ... ... ... ..1 ...

r3c23"'1' + r2c6='1' => r1c8='1
both targets to '1'
and my error was to omit to check that this is not reversable

with r3c23='1' + r1c8='1' we are quickly here

Code: Select all: ... ... .1. ... 1.. ... .11 ... .. ... ... 1.. ... .1. ... 1.. ... ... ... ... ..1 .11 ... ... ... ..1 ...

so the first step of my path is wrong, and the second cannot be
'9' must be in the base
but '1' or '9' (or both ) must be in the base, so it can be the pair 48

by **champagne** » Tue Nov 18, 2025 7:00 am

Hi cenoman,

One question.

I came back on this puzzle to see what is still valid in my path.

I had a deeper look on your eliminations.

No problem with your -3 r2c45 (NBD in MN/locked 7)
no problem with -14 r2c6 (BD false in MN) another way to express that a digit can not be in both target

I don't see -5 r1c9 (NBD in TC)

ric9 is not a target cell, what means here (NBD in TC)

by **Cenoman** » Tue Nov 18, 2025 9:05 am

champagne wrote:
I don't see -5 r1c9 (NBD in TC)
ric9 is not a target cell, what means here (NBD in TC)

Hi champagne,
Thank you for spotting the typo (or failed copy-paste) I meant the same rationale as -3r2c45, i.e. Non base Digit in Mirror node, containing already locked NBD '7'. I have edited my post: -5r1c9 (NBD in MN/locked 7)
Note the important role of this elimination, as it yields alone quite all the other JE eliminations (all but -3r2c45), reaching thus the same resolution state as totuan's double exocets.

by **champagne** » Tue Nov 18, 2025 9:36 am

Cenoman wrote:
champagne wrote:
I don't see -5 r1c9 (NBD in TC)
ric9 is not a target cell, what means here (NBD in TC)

Hi champagne,
Thank you for spotting the typo (or failed copy-paste) I meant the same rationale as -3r2c45, i.e. Non base Digit in Mirror node, containing already locked NBD '7'. I have edited my post: -5r1c9 (NBD in MN/locked 7)
Note the important role of this elimination, as it yields alone quite all the other JE eliminations (all but -3r2c45), reaching thus the same resolution state as totuan's double exocets.

Agreed now although it''s not exactly the same wording.
And yes, we need one seat for '89' in the only 'mirror cell' so it can't be '5'

David made really a good job in the compendium

The New Sudoku Players' Forum

false TH sol 452307986

false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986

Re: false TH sol 452307986