You can start marketing in Korea using google adwords campaign.
Eventhough you don't have Korean landing page using main Korean keywords you can get client from Korea.
Also if you need Korean landing page I can make for you.
If you need to see the landing page sample I will provide to you.
For 5$ I can provide Korean Keywords and sentence for google adwords.
For extra 20$ I can provide Korean for landing page.
For extra 200$ I can provide Korean landing page.