diff --git a/src/lib/utils/contest.ts b/src/lib/utils/contest.ts
index fd7d3ae23..b14af591d 100644
--- a/src/lib/utils/contest.ts
+++ b/src/lib/utils/contest.ts
@@ -92,10 +92,11 @@ export const classifyContest = (contest_id: string) => {
   return null;
 };
 
-// HACK: As of December 2024, the following contests are applicable.
+// HACK: As of April 2025, the following contests are applicable.
 // Note: The classification logic may need to be revised when new contests are added.
 const ABC_LIKE: ContestPrefix = {
   aising2020: 'エイシング プログラミング コンテスト 2020',
+  hhkb2020: 'HHKB プログラミングコンテスト 2020',
   panasonic2020: 'パナソニックプログラミングコンテスト 2020',
 } as const;
 const abcLikePrefixes = new Set(getContestPrefixes(ABC_LIKE));
diff --git a/src/test/lib/utils/test_cases/contest_type.ts b/src/test/lib/utils/test_cases/contest_type.ts
index 8e0c6eaf0..56fa50b6c 100644
--- a/src/test/lib/utils/test_cases/contest_type.ts
+++ b/src/test/lib/utils/test_cases/contest_type.ts
@@ -191,6 +191,10 @@ export const abcLike = [
     contestId: 'aising2020',
     expected: ContestType.ABC_LIKE,
   }),
+  createTestCaseForContestType('HHKB 2020')({
+    contestId: 'hhkb2020',
+    expected: ContestType.ABC_LIKE,
+  }),
   createTestCaseForContestType('Panasonic 2020')({
     contestId: 'panasonic2020',
     expected: ContestType.ABC_LIKE,