diff --git a/src/arcaea_offline/database.py b/src/arcaea_offline/database.py
index 95dd992..20adeef 100644
--- a/src/arcaea_offline/database.py
+++ b/src/arcaea_offline/database.py
@@ -8,6 +8,7 @@ from typing import Callable, List, NamedTuple, Optional, TypeVar, Union
 from thefuzz import fuzz
 from thefuzz import process as fuzz_process
 
+from .external import ExternalScoreItem
 from .init_sqls import INIT_SQLS
 from .models import (
     DbAliasRow,
@@ -116,6 +117,30 @@ class Database(metaclass=Singleton):
             conn.commit()
         self.__trigger_update_hooks()
 
+    @check_conn
+    def import_external(self, external_scores: List[ExternalScoreItem]):
+        for external in external_scores:
+            # 2017 Jan. 22, 00:00, UTC+8
+            time = external.time if external.time > -1 else 1485014400
+            pure = external.pure if external.pure > -1 else None
+            far = external.far if external.far > -1 else None
+            lost = external.lost if external.lost > -1 else None
+            max_recall = external.max_recall if external.max_recall > -1 else None
+            clear_type = external.clear_type if external.clear_type > -1 else None
+
+            score = ScoreInsert(
+                song_id=external.song_id,
+                rating_class=external.rating_class,
+                score=external.score,
+                time=time,
+                pure=pure,
+                far=far,
+                lost=lost,
+                max_recall=max_recall,
+                clear_type=clear_type,
+            )
+            self.insert_score(score)
+
     @check_conn
     def init(self):
         create_sqls = INIT_SQLS[1]["init"]
diff --git a/src/arcaea_offline/external.py b/src/arcaea_offline/external.py
new file mode 100644
index 0000000..942afd3
--- /dev/null
+++ b/src/arcaea_offline/external.py
@@ -0,0 +1,60 @@
+import dataclasses
+import sqlite3
+from typing import List, Union
+
+
+@dataclasses.dataclass
+class ExternalScoreItem:
+    song_id: str
+    rating_class: int
+    score: int
+    pure: int = -1
+    far: int = -1
+    lost: int = -1
+    max_recall: int = -1
+    clear_type: int = -1
+    time: int = -1
+
+
+class ExternalScoreSource:
+    def get_score_items(self) -> List[ExternalScoreItem]:
+        ...
+
+
+class St3ScoreSource(ExternalScoreSource):
+    db_path: Union[str, bytes]
+    CLEAR_TYPES_MAP = {0: -1, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1}
+
+    def __init__(self, db_path: Union[str, bytes]):
+        self.db_path = db_path
+
+    def get_score_items(self):
+        items = []
+        with sqlite3.connect(self.db_path) as st3_conn:
+            cursor = st3_conn.cursor()
+            db_scores = cursor.execute(
+                "SELECT songId, songDifficulty, score, perfectCount, nearCount, missCount, date FROM scores"
+            ).fetchall()
+            for song_id, rating_class, score, pure, far, lost, date in db_scores:
+                db_clear_type = cursor.execute(
+                    "SELECT clearType FROM cleartypes WHERE songId = ? AND songDifficulty = ?",
+                    (song_id, rating_class),
+                ).fetchone()[0]
+                clear_type = self.CLEAR_TYPES_MAP[db_clear_type]
+
+                date_str = str(date)
+                date = None if len(date_str) < 7 else int(date_str.ljust(11, "0"))
+
+                kwargs = {
+                    "song_id": song_id,
+                    "rating_class": rating_class,
+                    "score": score,
+                    "pure": pure,
+                    "far": far,
+                    "lost": lost,
+                    "clear_type": clear_type,
+                }
+                if date:
+                    kwargs["time"] = date
+                items.append(ExternalScoreItem(**kwargs))
+        return items