## Is this a BUG+2?

Post the puzzle or solving technique that's causing you trouble and someone will help

### Is this a BUG+2?

7352684911849735622..541387.13.24.7547.3.521652.71..433421.765..51.3.724..745213.
Some solvers may put a 6 at r8c1 but this can’t be true, so there are two 3-candidate cells.
The BUG-stopping candidates are 9 at r6c3 and also 9 at r9c1. What can be inferred from this?
That BOTH must be true, that AT LEAST ONE must be true, or that ONE ONLY must be true?
Is there some other technique which could be applied here?
Yogi
Yogi
2017 Supporter

Posts: 185
Joined: 05 December 2015
Location: New Zealand

### Re: Is this a BUG+2?

Code: Select all
`+----------------+----------------+----------------+| 7    3    5    | 2    6    8    | 4    9    1    || 1    8    4    | 9    7    3    | 5    6    2    || 2    69   69   | 5    4    1    | 3    8    7    |+----------------+----------------+----------------+| 6-9  1    3    | 68   2    4    | 89   7    5    || 4    7    89   | 3    89   5    | 2    1    6    || 5    2    68+9 | 7    1    69   | 89   4    3    |+----------------+----------------+----------------+| 3    4    2    | 1    89   7    | 6    5    89   || 89   5    1    | 68   3    69   | 7    2    4    || 68+9 69   7    | 4    5    2    | 1    3    89   |+----------------+----------------+----------------+`

Yes, you can solve it with a BUG+2. Either r6c3=9 or r9c1=9 (or both) => -9r4c1
Alternatively there is an xy-wing or a w-wing.
eleven

Posts: 2468
Joined: 10 February 2008

### Re: Is this a BUG+2?

Great. Thanx.
Yogi
2017 Supporter

Posts: 185
Joined: 05 December 2015
Location: New Zealand