phranque - 11:00 am on Jun 1, 2013 (gmt 0)
Changed the file name from:
(underscore instead of hyphen) WITHOUT doing any 301 redirects, and it STILL can't be found for the term blue widgets.
fyi a hyphen is a word separator and an underscore is NOT a word separator.
regardless of the file name - if your content is actually about blue widgets and you filter all other competing results out using the site: operator, you should be able to get that page ranking unless you have stronger signals on some of your other pages.
after looking into tedster's suggestion, you might also investigate inbound links to the other higher ranking pages as well as your internal linking to see if something weird is happening with PR and relevance.