diff --git a/Assets/Cryville/Crtr/Judge.cs b/Assets/Cryville/Crtr/Judge.cs
index cf61135..febfaaa 100644
--- a/Assets/Cryville/Crtr/Judge.cs
+++ b/Assets/Cryville/Crtr/Judge.cs
@@ -1,7 +1,10 @@
 using Cryville.Common;
+using Cryville.Common.Buffers;
 using Cryville.Common.Pdt;
 using Cryville.Crtr.Event;
+using System;
 using System.Collections.Generic;
+using System.Globalization;
 
 namespace Cryville.Crtr {
 	public class Judge {
@@ -30,14 +33,7 @@ namespace Cryville.Crtr {
 		public Judge(PdtRuleset rs) {
 			_etor = ChartPlayer.etor;
 			_rs = rs;
-			foreach (var s in rs.scores) {
-				var key = s.Key;
-				scoreSrcs.Add(key.Key, new PropSrc.Float(() => scores[key.Key]));
-				scoreOps.Add(key.Key, new PropOp.Float(v => scores[key.Key] = v));
-				scoreFmtKeys.Add(key.Key, IdentifierManager.SharedInstance.Request("_score_" + (string)key.Name));
-				scoreDefs.Add(key.Key, s.Value);
-				scores.Add(key.Key, s.Value.init);
-			}
+			InitScores();
 		}
 		public void Prepare(float st, float et, Identifier input, JudgeDefinition def, ContainerState container) {
 			List<JudgeEvent> list;
@@ -166,42 +162,95 @@ namespace Cryville.Crtr {
 				var key = scoreop.Key;
 				_etor.ContextSelfValue = scoreSrcs[key.name.Key];
 				_etor.Evaluate(scoreOps[key.name.Key], scoreop.Value);
-				scoreSrcs[key.name.Key].Invalidate();
+				InvalidateScore(key.name.Key);
 				foreach (var s in _rs.scores) {
 					if (s.Value.value != null) {
 						_etor.ContextSelfValue = scoreSrcs[s.Key.Key];
 						_etor.Evaluate(scoreOps[s.Key.Key], s.Value.value);
-						scoreSrcs[s.Key.Key].Invalidate();
+						InvalidateScore(s.Key.Key);
 					}
 				}
 			}
-			ScoreCache.Clear();
 		}
-		readonly Dictionary<int, int> scoreFmtKeys = new Dictionary<int, int>();
+		readonly Dictionary<int, int> scoreStringKeys = new Dictionary<int, int>();
+		readonly Dictionary<int, int> scoreStringKeysRev = new Dictionary<int, int>();
 		readonly Dictionary<int, PropSrc> scoreSrcs = new Dictionary<int, PropSrc>();
 		readonly Dictionary<int, PropOp> scoreOps = new Dictionary<int, PropOp>();
 		readonly Dictionary<int, ScoreDefinition> scoreDefs = new Dictionary<int, ScoreDefinition>();
-		public readonly Dictionary<int, float> scores = new Dictionary<int, float>();
-		readonly Dictionary<int, string> ScoreCache = new Dictionary<int, string>();
-		readonly object _lock = new object();
-		public Dictionary<int, string> GetFormattedScoreStrings() {
-			lock (_lock) {
-				if (ScoreCache.Count == 0) {
-					foreach (var s in scores)
-						ScoreCache.Add(scoreFmtKeys[s.Key], s.Value.ToString(scoreDefs[s.Key].format));
-				}
-				return ScoreCache;
+		readonly Dictionary<int, float> scores = new Dictionary<int, float>();
+		readonly Dictionary<int, string> scoreStringCache = new Dictionary<int, string>();
+		readonly Dictionary<int, PropSrc> scoreStringSrcs = new Dictionary<int, PropSrc>();
+		readonly ArrayPool<byte> scoreStringPool = new ArrayPool<byte>();
+		void InitScores() {
+			foreach (var s in _rs.scores) {
+				var key = s.Key.Key;
+				var strkey = IdentifierManager.SharedInstance.Request("_score_" + (string)s.Key.Name);
+				scoreStringKeys.Add(key, strkey);
+				scoreStringKeysRev.Add(strkey, key);
+				scoreSrcs.Add(key, new PropSrc.Float(() => scores[key]));
+				scoreOps.Add(key, new PropOp.Float(v => scores[key] = v));
+				scoreDefs.Add(key, s.Value);
+				scores.Add(key, s.Value.init);
+				scoreStringCache.Add(scoreStringKeys[key], null);
+				scoreStringSrcs.Add(scoreStringKeys[key], new ScoreStringSrc(scoreStringPool, () => GetScoreString(strkey)));
 			}
 		}
+		void InvalidateScore(int key) {
+			scoreSrcs[key].Invalidate();
+			scoreStringCache[scoreStringKeys[key]] = null;
+			scoreStringSrcs[scoreStringKeys[key]].Invalidate();
+		}
+		string GetScoreString(int key) {
+			var result = scoreStringCache[key];
+			if (result == null) {
+				var rkey = scoreStringKeysRev[key];
+				return scoreStringCache[key] = scores[rkey].ToString(scoreDefs[rkey].format, CultureInfo.InvariantCulture);
+			}
+			else return result;
+		}
+		public bool TryGetScoreSrc(int key, out PropSrc value) {
+			return scoreSrcs.TryGetValue(key, out value);
+		}
+		public bool TryGetScoreStringSrc(int key, out PropSrc value) {
+			return scoreStringSrcs.TryGetValue(key, out value);
+		}
 		public string GetFullFormattedScoreString() {
 			bool flag = false;
 			string result = "";
-			foreach (var s in GetFormattedScoreStrings()) {
-				result += string.Format(flag ? "\n{0}: {1}" : "{0}: {1}", IdentifierManager.SharedInstance.Retrieve(s.Key), s.Value);
+			foreach (var s in scores.Keys) {
+				result += string.Format(flag ? "\n{0}: {1}" : "{0}: {1}", IdentifierManager.SharedInstance.Retrieve(s), GetScoreString(scoreStringKeys[s]));
 				flag = true;
 			}
 			return result;
 		}
+		class ScoreStringSrc : PropSrc {
+			readonly Func<string> _cb;
+			readonly ArrayPool<byte> _pool;
+			byte[] _buf;
+			public ScoreStringSrc(ArrayPool<byte> pool, Func<string> cb) {
+				_pool = pool;
+				_cb = cb;
+			}
+			public override void Invalidate() {
+				base.Invalidate();
+				if (_buf != null) {
+					_pool.Return(_buf);
+					_buf = null;
+				}
+			}
+			protected override unsafe void InternalGet(out int type, out byte[] value) {
+				var src = _cb();
+				int strlen = src.Length;
+				type = PdtInternalType.String;
+				value = _pool.Rent(sizeof(int) + strlen * sizeof(char));
+				fixed (byte* _ptr = value) {
+					char* ptr = (char*)(_ptr + sizeof(int));
+					*(int*)_ptr = strlen;
+					int i = 0;
+					foreach (var c in src) ptr[i++] = c;
+				}
+			}
+		}
 	}
 	public class InputDefinition {
 		public int dim;
diff --git a/Assets/Cryville/Crtr/PdtEvaluator.cs b/Assets/Cryville/Crtr/PdtEvaluator.cs
index 026f813..ef6160a 100644
--- a/Assets/Cryville/Crtr/PdtEvaluator.cs
+++ b/Assets/Cryville/Crtr/PdtEvaluator.cs
@@ -23,8 +23,6 @@ namespace Cryville.Crtr {
 			else {
 				var id = new Identifier(name);
 				PropSrc prop;
-				string str;
-				float num;
 				if (ContextEvent != null && ContextEvent.PropSrcs.TryGetValue(name, out prop)) {
 					prop.Get(out type, out value);
 				}
@@ -32,15 +30,12 @@ namespace Cryville.Crtr {
 					var vec = ContextState.GetRawValue(id);
 					new VectorSrc(() => vec).Get(out type, out value);
 				}
-				else if (ContextJudge != null && ContextJudge.scores.TryGetValue(name, out num)) {
-					type = PdtInternalType.Number;
-					LoadNum(num);
-					value = _numbuf;
+				else if (ContextJudge != null && ContextJudge.TryGetScoreSrc(name, out prop)) {
+					prop.Get(out type, out value);
 					RevokePotentialConstant();
 				}
-				else if (ContextJudge != null && ContextJudge.GetFormattedScoreStrings().TryGetValue(name, out str)) {
-					type = PdtInternalType.String;
-					value = GetBytes(str);
+				else if (ContextJudge != null && ContextJudge.TryGetScoreStringSrc(name, out prop)) {
+					prop.Get(out type, out value);
 					RevokePotentialConstant();
 				}
 				else {
diff --git a/Assets/Cryville/Crtr/PropSrc.cs b/Assets/Cryville/Crtr/PropSrc.cs
index 5ce80d1..3519932 100644
--- a/Assets/Cryville/Crtr/PropSrc.cs
+++ b/Assets/Cryville/Crtr/PropSrc.cs
@@ -6,7 +6,7 @@ namespace Cryville.Crtr {
 	public abstract class PropSrc {
 		int _type;
 		byte[] _buf = null;
-		public void Invalidate() { _buf = null; }
+		public virtual void Invalidate() { _buf = null; }
 		public void Get(out int type, out byte[] value) {
 			if (_buf == null) InternalGet(out _type, out _buf);
 			type = _type;