I have seen several comments that empty rectangles fall into a category of difficult useless strategies.  Although only one candidate is removed, I find them an easy to spot pattern with a moderate frequency of occurrence.  I wonder if the reluctance to use them is because of a poor explanation of what to look for.  The name “empty rectangle” is confusing.  What is ‘in’ the box is important.  Candidates in one box confined to one row and one column and simple intersection strategy. Is the attached doc. a better explanation?

I wish the alternating inference network was as easy.  Seems to be a must for the very difficult puzzles. I am studying “fenyx’s” technique but not sure I can master it.    

 im  sry i did find that i posted this before awhile back...i recalled looking at the ones in this puzz and continued on to other things but looked again at them and i ONLY removed the SINGLE ones left over after i circled only 2 in a line in a box.....the right one has to be in the circle but dont no which one so hoping it will get you more plays(and to date it has) might even b a name for this but its very easy to do it this way .... if u think of it as a wag that would be beside the point(just keep it to urself and move on) but u solved it

 this is brainbashers aug19 superhard and i pulled the 7s out .....there are more (lots of) ways to solve it but this again became interesting....if u look hard enough C3 would be removed because of G3=b  and C9=A so that would make A3 the B   right????? yup  which would remove the 7 from A7......now look long enough and ull c the only place for a B making it the 7.....this is a very simple thing to find if ur stuck.....good name would be  duhhhhhh ok  the A/B solution.....lots an lots of em and as easy as the xwing (while u search for em)   help the dummies like me do the tough ones without a puter program.....