From Just Solve the File Format Problem
OLE compound document format.HWP is Hancom Word's file format, and is based on Microsoft's
A specification was released in 2010, but it is in Korean only.
- Questions on POLE library (and HancomWord support) Provides basic info on the format.
-  Further post in the thread, linking to the specification download page, and telling how to download and extract it properly.
- Hancom Word specification Make sure to read the post above.