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by **ArkieTech** » Fri Jan 17, 2014 12:31 am

Code: Select all: *-----------* |9..|62.|...| |..8|.1.|5.7| |3..|..7|...| |---+---+---| |...|2..|.95| |5..|.7.|..2| |43.|..8|...| |---+---+---| |...|7..|..1| |2.6|.3.|7..| |...|.61|..3| *-----------*

Play/Print this puzzle online

by **Leren** » Fri Jan 17, 2014 1:37 am

Code: Select all: *--------------------------------------------------------------* | 9 7 b145 | 6 2 c45 | 348 1348 48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 15-4 |d45 8 7 | 269 1246 49 | |--------------------+--------------------+--------------------| | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | |--------------------+--------------------+--------------------| | 8 459 3 | 7 59 2 | 69 456 1 | | 2 1 6 | 4589 3 45 | 7 458 489 | | 7 459 a45 | 589-4 6 1 | 29 2458 3 | *--------------------------------------------------------------*

M Wing Type 2C a=5, b=4: (4=5) r9c3 - r1c3 = (5-4) r1c6 = (4) r3c4 => - 4 r3c3, r9c4; lclste

Leren

by **pjb** » Fri Jan 17, 2014 1:38 am

A real life solution: An X-Wing of 4s at r27c28 leads to -

Code: Select all: 9 7 c145 | 6 2 b45 | 38 138 48 6 24 8 | 3 1 9 | 5 24 7 3 25 15-4 |a45 8 7 | 269 126 49 ---------------------+----------------------+--------------------- 1 68 7 | 2 4 36 | 38 9 5 5 68 9 | 1 7 36 | 4 38 2 4 3 2 | 59 59 8 | 1 7 6 ---------------------+----------------------+--------------------- 8 459 3 | 7 59 2 | 69 456 1 2 1 6 | 4589 3 45 | 7 58 489 7 59 d45 | 589-4 6 1 | 29 258 3

Then: (4=5) r3c4 - r1c6 = r1c3 - (5=4) r9c => -4 r3c3, r9c4; stte

Phil

by **SteveG48** » Fri Jan 17, 2014 2:44 am

Code: Select all: *-----------------------------------------------------------* | 9 7 ah145 | 6 2 b45 | 348 1348 g48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 di145 |c45 8 7 | 269 1246 d49 | *-------------------+-------------------+-------------------| | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | *-------------------+-------------------+-------------------| | 8 459 3 | 7 59 2 | 69 456 1 | | 2 1 6 |d4589 3 e45 | 7 458 f489 | | 7 459 4-5 |d4589 6 1 | 29 2458 3 | *-----------------------------------------------------------*

A not so real-life solution:

(5)r1c3 = r1c6 - (5=4)r3c4 - r3c39|r89c4 = r8c6 - r8c9 = r1c9 - (4=1)r1c3 - (1=5)r3c3 => -5 r9c3 ; stte

by **tlanglet** » Fri Jan 17, 2014 4:25 am

Code: Select all: *-----------------------------------------------------------* | 9 7 *45=1 | 6 2 *f45 | 348 a1348 48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 15-4 |*g45 8 7 |c269 b1246 49 | |-------------------+-------------------+-------------------| | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | |-------------------+-------------------+-------------------| | 8 459 3 | 7 d59 2 |d69 456 1 | | 2 1 6 | 4589 3 e4*5 | 7 458 489 | | 7 459 *45 | 589-4 6 1 | 29 2458 3 | *-----------------------------------------------------------*

Almost Remote Pair (45)r3c4 , (45)r1c6, (45=1)r1c3, (45)r9c3
[RP(45) => r9c4, r3c3<>4] = [1r1c3-1r1c8=(1-6)r3c8=6r3c7-(6=95)r7c75-(5=4)r8c6*-4r1c6=4r3c4 => r9c4*, r3c3<>4

Ted

by **Marty R.** » Fri Jan 17, 2014 6:11 pm

Code: Select all: +-----------+------------+--------------+ | 9 7 145 | 6 2 45 | 348 1348 48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 145 | 45 8 7 | 269 1246 49 | +-----------+------------+--------------+ | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | +-----------+------------+--------------+ | 8 459 3 | 7 59 2 | 69 456 1 | | 2 1 6 | 4589 3 45 | 7 458 489 | | 7 459 45 | 4589 6 1 | 29 2458 3 | +-----------+------------+--------------+

Play this puzzle online at the Daily Sudoku site

(4=9)r3c9-r8c9=r8c4-(9=5)r7c5-(5=4)r8c6=>r8c9<>4

by **daj95376** » Sat Jan 18, 2014 7:31 am

An obscure UR with a powerful elimination. (Yes, it's from my solver.)

Code: Select all: +--------------------------------------------------------------+ | 9 7 145 | 6 2 45 | 348 1348 48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 145 | 45 8 7 | 269 1246 49 | |--------------------+--------------------+--------------------| | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | |--------------------+--------------------+--------------------| | 8 459 3 | 7 59 2 | 69 456 1 | | 2 1 6 | *48+59 3 45 | 7 *48+5 489 | | 7 459 45 | *48+59 6 1 | 29 *48+25 3 | +--------------------------------------------------------------+ # 57 eliminations remain r89c48 <48> UR via s-link <> 4 r8c8 extraneous r89c48 <48> UR via s-link + (4=5)r8c6 <> 4 r9c4 necessary

by **tlanglet** » Sat Jan 18, 2014 2:08 pm

daj95376 wrote:An obscure UR with a powerful elimination. (Yes, it's from my solver.)

Code: Select all
+--------------------------------------------------------------+ | 9 7 145 | 6 2 45 | 348 1348 48 | | 6 24 8 | 3 1 9 | 5 24 7 | | 3 245 145 | 45 8 7 | 269 1246 49 | |--------------------+--------------------+--------------------| | 1 68 7 | 2 4 36 | 38 9 5 | | 5 68 9 | 1 7 36 | 348 348 2 | | 4 3 2 | 59 59 8 | 1 7 6 | |--------------------+--------------------+--------------------| | 8 459 3 | 7 59 2 | 69 456 1 | | 2 1 6 | *48+59 3 45 | 7 *48+5 489 | | 7 459 45 | *48+59 6 1 | 29 *48+25 3 | +--------------------------------------------------------------+ # 57 eliminations remain r89c48 <48> UR via s-link <> 4 r8c8 extraneous r89c48 <48> UR via s-link + (4=5)r8c6 <> 4 r9c4 necessary

Danny,

That is a very interesting bit of logic you identified. Elimination of 4 in r8c9 has the identical result as the obscure UR.

(4-9)r8c9=9r8c4-(9=5)r7c5-(5=4)r8c6 Contradiction => r8c9<>4

Ted

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