I once heard of something I thought was called the "wooba". I thought
it was the imperfection in an otherwise perfect work of art. That
imperfection was highly reguarded as what made it art as opposed to
perfection. The idea is pure paradox in that the imperfection then
makes it perfect. Again, I thought it was Japanese in derivation. What
is the actual term for that irregularity that actually makes the art
perfect?

Hello

I believe that you're thinking of the word "wabi."


From the Voice of America Wordmaster:

"The Japanese word 'wabi' that has to do with a certain kind of beauty
that generally Americans have not appreciated as much. It's the kind
of beauty of a pot that has a crack in it. Maybe the beauty of the
Liberty Bell."
http://www.manythings.org/voa/wm/wm118.html

Also see:

"Wabi
 Of all the words in all the languages of the world, the one I love
best is the Japanese term, wabi. It refers to a captivating work of
art with a distinctive, beautiful flaw that embodies the idiosyncratic
humanity of its creator.
 An aqua groove in an otherwise perfectly green ceramic pot may give
it wabi. A skilled blues singer who intentionally wails out of pitch
for a moment may be demonstrating wabi.
 Wabi is rooted in the idea that perfection is a kind of death."
source: freewillastrology.com
http://www.freewillastrology.com/beauty/beauty.main68.shtml

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search strategy:
"an imperfection in an otherwise"
"japanese word wabi"

Thanks.