I am writing an article, and trying to find out when the Eberhard
Faber Blackwing 602 pencil was first put on the market.  I know that
the name was trademarked by the company in 1933.  Eberhard Faber was
sold to Faber-Castell in 1987, which, in turn, was sold to Sanford (a
division of Newell-Rubbermaid) in 1994.  The Blackwing was
discontinued in 1998.  Sanford has not kept the Eberhard Faber
archives, so it is unable to answer the question.

Some clues: I have serached some issues of a Trade Journal called
"Modern Stationer" (which was published between 1920 and 1964),
looking for an announcement of the Blackwing in the "New on the
Market" section or an advertisement.  I have yet to find a reference,
and am away from the library that has the magazine (the Library of
Science Industry and Business in NYC) while I'm writing.  The
Blackwing may also have been advertised in Time, the Saturday Evening
Post, and Literary Digest.  It definitely advertyised in The New
Yorker.

Another possible source: Eberhard Faber catalogues or office supply
catalogues.

I'd love to find this out -- especially including early advertising
slogans -- and, jeez, I've set you out on the right
foot.

I found a "famous slogan" "half the pressure, twice the speed"
http://www.pencilpages.com/articles/blackwing.htm

nothing more at this point about a date when it began.

Greetings!  The Internet has little information on the Blackwing 602
so I have emailed Eberhard Faber to see if they can assist in your
query.  If they reply with pertinent information, I will post it as an
answer.