Using backslash in query

I'm afraid I'm confused about something very simple... but anyway

I need to run a query on a varchar field containing a backslash.
My first attempt looked like this: SELECT smth. FROM  tbl WHERE situation LIKE '%\\%';
This did not returned any rows.

I looked up for a reference, confirmed that
"... double-backslash is required to represent a literal backslash."
http://www.postgresql.org/docs/aw_pgsql_book/node139.html#copy_backslash_han
dling

But when I doubled the number of backslashes: SELECT smth. FROM  tbl WHERE situation LIKE '%\\\\%';
- it actually worked fine.

Same thing happens with using regex: situation ~ '\\';

Could someone shed some light on this, please.

Mike.