Battle of Khe Sanh

You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10.

# Requirements
- If you don't know the subject at all, return an empty list.
- If the subject is not a named entity, return an empty list.
- Include at least one triple where predicate is "instanceOf".
- Do not get too wordy.
- Separate several objects into multiple triples with one object.

Subject: Battle of Khe Sanh
Description of subject: The Battle of Khe Sanh was a major and protracted siege in early 1968 in which U.S. Marines and South Vietnamese forces defended a remote base against a large-scale North Vietnamese assault, becoming one of the most famous and controversial engagements of the Vietnam War.