Puzzle Corner

These are too easy now...

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...but for more of a challenge: what is the minimum number of inferences required, and which are they?

To be clear: an "inference" is a square not forced by the rules at the time it is filled in, but would lead to a breaking of the rules later if filled in with the other symbol. The rules are: 1. 3 O's and 3 X's in every row and column; 2. not allowed a string of 3 O's or 3 X's in any row or column. Thus: X in C3 is not an inference, because O breaks the rules immediately.

F2, B2
 
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Black Hole said:
...but for more of a challenge: what is the minimum number of inferences required, and which are they?
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I think you're probably right. After completing the puzzle with as many inferences as it took using my scatterbrain approach, I tried again. Thought I could do it in two, but then I found I was stuck and had to resort to both (ends-1) of row 1 (after the simple moves) - thus making 4. I can't see an obvious way of only one inference.
 
It’s a Saturday one. Third week where I managed without guessing. Is it just me or was this one easy?
 
That didn't appear too difficult either. So that's the theory about an easy one and a difficult one kyboshed. (And not koshered as the autocorrect/spellchecker wanted.)
 
Black Hole said:
Yes. I spent a while on the logic until I realised there is no logical solution... and the reason is that there are two solutions.
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Please would you post both of those. I can only see one solution and I'm not aware that I used trial and error, but perhaps I made a mistake somewhere and got lucky.
 
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