There was an explanation in an RPG book that in 2218 a Federation ship found Qo'nos and after a short observation (so they didn't really know what the Klingons were like) they made immediate contact. The Klingons then slaughtered the crew, stole their ship and reverse engineered Federation technology to catapult the Klingon Empire into a s Spacefaring Superpower.
The tied the 2218 and 2223 things together by saying it took the Klingons 5 years to fully reverse-engineer the stolen tech and set up their first colonies and spacefleets, so full on hostile space contact between the Feds and the Klingons didn't happen until 2223.
The tied the 2218 and 2223 things together by saying it took the Klingons 5 years to fully reverse-engineer the stolen tech and set up their first colonies and spacefleets, so full on hostile space contact between the Feds and the Klingons didn't happen until 2223.