... by: Robert

Follow up to my earlier comment.

If some additional techniques are used, the number of candidates to be eliminated by forcing nets is not so large. In particular, using an extended version of Medusa is very helpful,

Rule 6 in Medusa allows one to draw an inference when a particular colour would empty some sell - the other colour must therefore be the one that is "on". However, there could just as well be a rule for emptying a unit - if one of the colours eliminates every candidate with value of 6 from the seventh row, for example, then the other colour must be the one that is "on". This possible extension to Medusa is mentioned in the comments (including in a comment by me) on the strategy overview page.

But if you use that extension to Medusa, then elimination of A1-1 and A1-2 with forcing nets is sufficient to solve the puzzle. No "fancy" extensions to a forcing net are necessary, e.g., no groups or almost locked sets or anything like that.

Medusa is mostly a subset of AICs, except for rule 6, which has something of the flavour of a forcing net about it. Extending rule 6 to include "unit emptying" as well as "cell emptying" appears to do some of the same work done by forcing nets in my earlier analysis.

... by: Frans Goosens

With trial and error

Combination B1=146 and F7=239

************************************************************
B1=1 F7=2 Wrong, Undo calculation

All reset to initial position

************************************************************
B1=1 F7=3 Wrong, Undo calculation

All reset to initial position

************************************************************
B1=1 F7=9 Wrong, Undo calculation

All reset to initial position

************************************************************
B1=4 F7=2 ( B9=7 ) Solved,


#463--------------------------Solution
070 008 000-------------672 548 391
003 200 800-------------453 219 867
900 000 004-------------981 637 524

000 090 050-------------824 391 756
006 000 100-------------796 825 143
010 760 080-------------315 764 289

500 000 002-------------537 486 912
008 002 400-------------168 972 435
000 100 070-------------249 153 678

Total solving time is : 58 sec.
Number of logical steps is : 4611

... by: Hello!

| 6 7 2 | 5 4 8 | 3 9 1 |
| 4 5 3 | 2 1 9 | 8 6 7 |
| 9 8 1 | 6 3 7 | 5 2 4 |

| 8 2 4 | 3 9 1 | 7 5 6 |
| 7 9 6 | 8 2 5 | 1 4 3 |
| 3 1 5 | 7 6 4 | 2 8 9 |

| 5 3 7 | 4 8 6 | 9 1 2 |
| 1 6 8 | 9 7 2 | 4 3 5 |
| 2 4 9 | 1 5 3 | 6 7 8 |

... by: Robert

Use basic techniques plus AICs with groups, almost locked sets.

When stuck, applying forcing nets. When candidate is eliminated by forcing net, go back to basic techniques and AICs with groups and almost locked sets.

Forcing net candidates: A1-1, A1-4, A3-1, A3-5, A4-4, A4-9

Puzzle can be solved in this way.

... by: numpl_npm

SE9.0

8C2 1D6 2E5 4E8 8G5 8J9

| _ 7 _ | _ _ 8 | _ _ _ | A
| _ _ 3 | 2 _ _ | 8 _ _ | B
| 9 8 _ | _ _ _ | _ _ 4 | C

| _ _ _ | _ 9 1 | _ 5 _ | D
| _ _ 6 | _ 2 _ | 1 4 _ | E
| _ 1 _ | 7 6 _ | _ 8 _ | F

| 5 _ _ | _ 8 _ | _ _ 2 | G
| _ _ 8 | _ _ 2 | 4 _ _ | H
| _ _ _ | 1 _ _ | _ 7 8 | J

17G3.H1

3E9 ->
| 9F9 5E6 9E2 9J3
| 9AG7=[9A7 9B6|9G7 9H4 9B6]=9B6
| solved with basics

-3E9 ->
| [79]E9 [79]E12
| | 7E12 -> 7E1 9E9 contra. with basics
| | 9E12 ->
| | | 9E2 7E9 7C7 9J3 79BG6
| | | 4AD3=[4A3 4B5 7H5 7D1|4D3 7D1]=7D1
| | | contra. with basics

... by: James Havard

Bottom box row 4 subs 19 seconds. H8=3 with J6=3 gives a singles solution.