Company C, 1st Battalion, 20th Infantry Regiment
E136553
Company C, 1st Battalion, 20th Infantry Regiment was a U.S. Army infantry company in the Vietnam War, historically infamous for its central role in the 1968 My Lai massacre.
All labels observed (5)
How this entity was disambiguated
This entity first appeared as the object of triple T1196943 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Company C, 1st Battalion, 20th Infantry Regiment Context triple: [My Lai massacre, perpetratorUnit, Company C, 1st Battalion, 20th Infantry Regiment]
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A.
U.S. 23rd Infantry Regiment
The U.S. 23rd Infantry Regiment is a historic United States Army infantry unit renowned for its combat service in major conflicts including World War II and the Korean War.
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B.
2nd Ranger Battalion
The 2nd Ranger Battalion is an elite U.S. Army light infantry unit specializing in airborne and direct-action special operations missions.
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C.
1st Reconnaissance Battalion
The 1st Reconnaissance Battalion is an elite United States Marine Corps unit specializing in advanced reconnaissance and surveillance operations in support of Marine Air-Ground Task Forces.
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D.
1st Light Armored Reconnaissance Battalion
The 1st Light Armored Reconnaissance Battalion is a United States Marine Corps unit specializing in fast, armored reconnaissance and security operations using light armored vehicles.
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E.
1st Ranger Battalion
The 1st Ranger Battalion is an elite U.S. Army light infantry special operations unit renowned for its rapid-deployment capabilities and participation in high-risk missions worldwide.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Company C, 1st Battalion, 20th Infantry Regiment Target entity description: Company C, 1st Battalion, 20th Infantry Regiment was a U.S. Army infantry company in the Vietnam War, historically infamous for its central role in the 1968 My Lai massacre.
-
A.
U.S. 23rd Infantry Regiment
The U.S. 23rd Infantry Regiment is a historic United States Army infantry unit renowned for its combat service in major conflicts including World War II and the Korean War.
-
B.
2nd Ranger Battalion
The 2nd Ranger Battalion is an elite U.S. Army light infantry unit specializing in airborne and direct-action special operations missions.
-
C.
1st Reconnaissance Battalion
The 1st Reconnaissance Battalion is an elite United States Marine Corps unit specializing in advanced reconnaissance and surveillance operations in support of Marine Air-Ground Task Forces.
-
D.
1st Light Armored Reconnaissance Battalion
The 1st Light Armored Reconnaissance Battalion is a United States Marine Corps unit specializing in fast, armored reconnaissance and security operations using light armored vehicles.
-
E.
1st Ranger Battalion
The 1st Ranger Battalion is an elite U.S. Army light infantry special operations unit renowned for its rapid-deployment capabilities and participation in high-risk missions worldwide.
- F. None of above. chosen
Statements (25)
| Predicate | Object |
|---|---|
| instanceOf |
U.S. Army infantry company
ⓘ
military unit ⓘ |
| allegation |
mass killing of Vietnamese civilians
ⓘ
war crimes in Vietnam War ⓘ |
| associatedEvent | subsequent U.S. Army courts-martial related to My Lai ⓘ |
| associatedWith | Americal Division war crimes investigations ⓘ |
| branch | United States Army ⓘ |
| commandStructure | Americal Division ⓘ |
| conflict | Vietnam War ⓘ |
| country |
United States
ⓘ
linked to:
United States of America
|
| dateOfEventInvolvement | 1968-03-16 ⓘ |
| engagement | counterinsurgency operations in South Vietnam ⓘ |
| higherFormation | 11th Infantry Brigade ⓘ |
| historicalReputation | infamous for participation in My Lai massacre ⓘ |
| involvedIn | My Lai massacre ⓘ |
| locationOfEventInvolvement |
My Lai, Sơn Tịnh District, Quảng Ngãi Province, South Vietnam
ⓘ
linked to:
My Lai massacre
|
| notableCommander |
William L. Calley Jr.
ⓘ
linked to:
William Calley
|
| notableFor | central role in the My Lai massacre ⓘ |
| partOf | 1st Battalion, 20th Infantry Regiment ⓘ |
| role | infantry ⓘ |
| service | United States Army ground forces in Vietnam ⓘ |
| subunitOf | 20th Infantry Regiment ⓘ |
| theater | South Vietnam ⓘ |
| timePeriod | 1960s ⓘ |
| type | line infantry company ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
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.
Input
Subject: Company C, 1st Battalion, 20th Infantry Regiment Description of subject: Company C, 1st Battalion, 20th Infantry Regiment was a U.S. Army infantry company in the Vietnam War, historically infamous for its central role in the 1968 My Lai massacre.
Referenced by (8)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Company C, 1st Battalion, 20th Infantry Regiment
William Calley
→
unit
→
Company C, 1st Battalion, 20th Infantry Regiment, 11th Brigade, Americal Division
ⓘ
linked to: Company C, 1st Battalion, 20th Infantry Regiment
linked to: Company C, 1st Battalion, 20th Infantry Regiment
linked to: Company C, 1st Battalion, 20th Infantry Regiment
My Lai village
→
perpetratedByMilitaryUnit
→
U.S. Army Charlie Company, 1st Battalion, 20th Infantry Regiment
ⓘ
linked to: Company C, 1st Battalion, 20th Infantry Regiment
Task Force Barker
→
notableMemberUnit
→
Company C, 1st Battalion, 20th Infantry Regiment (Charlie Company)
ⓘ
linked to: Company C, 1st Battalion, 20th Infantry Regiment