from the Lufthansa Korean website:

"With the celebration of opening Incheon
International Airport on 29 March 2001, Lufthansa
offers you a chance to be upgraded.

Be our guest on this special promotion with
reasonable price. and enjoy Lufthansa Business
Class.

Economy Class (B or M Class
Tickets only) to Business Class

------ Upgrade (KRW350,000)

Period: 29 March 2001 - 15 June 2001( Departure date )

Oneway upgrade Incheon - Frankfurt only

Double upgrade or using other coupon combinations is not possible

How to request

First book Economy Class ( B or M Class ) and call us and request
your upgrade in between 72 hours before your departure ( request
earlier than 72 hours is not possible)
Purchase your voucher(MCO) for upgrade at Lufthansa counter and
deliver it to the staff at check-in counter.

For more details, please contact your travel agent or call us Tel:
3420-0400,3420-0420 "

BEWARE: even though it is not mentioned, the ticket must be issued in Seoul. I argued on the fact it is not mentioned but it was impossible to get anything from the Lufthansa staff ( black letter law...without law). Try your luck or buy your ticket in Seoul