diff --git a/src/boxes/future/mod.rs b/src/boxes/future/mod.rs
index 67338bac..8d0615f6 100644
--- a/src/boxes/future/mod.rs
+++ b/src/boxes/future/mod.rs
@@ -2,7 +2,7 @@
 // Nyashの箱システムによる非同期処理の基盤を提供します。
 // 参考: 既存Boxの設計思想
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use std::any::Any;
 use std::future::Future;
 use std::pin::Pin;
@@ -12,7 +12,7 @@ use std::sync::{Arc, Mutex};
 pub struct NyashFutureBox {
     pub result: Arc<Mutex<Option<Box<dyn NyashBox>>>>,
     pub is_ready: Arc<Mutex<bool>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl Clone for NyashFutureBox {
@@ -20,22 +20,17 @@ impl Clone for NyashFutureBox {
         Self {
             result: Arc::clone(&self.result),
             is_ready: Arc::clone(&self.is_ready),
-            id: self.id,
+            base: self.base.clone(),
         }
     }
 }
 
 impl NyashFutureBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         Self {
             result: Arc::new(Mutex::new(None)),
             is_ready: Arc::new(Mutex::new(false)),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -96,19 +91,42 @@ impl NyashBox for NyashFutureBox {
         "NyashFutureBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_future) = other.as_any().downcast_ref::<NyashFutureBox>() {
-            BoolBox::new(self.id == other_future.id)
+            BoolBox::new(self.base.id() == other_future.base.id())
         } else {
             BoolBox::new(false)
         }
     }
 }
 
+impl BoxCore for NyashFutureBox {
+    fn box_id(&self) -> u64 {
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let ready = *self.is_ready.lock().unwrap();
+        if ready {
+            let result = self.result.lock().unwrap();
+            if let Some(value) = result.as_ref() {
+                write!(f, "Future(ready: {})", value.to_string_box().value)
+            } else {
+                write!(f, "Future(ready: void)")
+            }
+        } else {
+            write!(f, "Future(pending)")
+        }
+    }
+}
+
+impl std::fmt::Display for NyashFutureBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 // Export NyashFutureBox as FutureBox for consistency
 pub type FutureBox = NyashFutureBox;
 
diff --git a/src/boxes/http/mod.rs b/src/boxes/http/mod.rs
index 9dc1c25e..9db85cfa 100644
--- a/src/boxes/http/mod.rs
+++ b/src/boxes/http/mod.rs
@@ -5,24 +5,21 @@
 // NOTE: HTTPサポートは現在開発中です。
 // reqwestクレートの依存関係のため、一時的に無効化されています。
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use crate::boxes::map_box::MapBox;
 use std::any::Any;
 use std::sync::{Arc, Mutex};
 
 #[derive(Debug, Clone)]
 pub struct HttpClientBox {
-    id: u64,
+    base: BoxBase,
 }
 
 impl HttpClientBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        HttpClientBox { id }
+        HttpClientBox { 
+            base: BoxBase::new() 
+        }
     }
     
     /// HTTP GETリクエスト（スタブ）
@@ -57,7 +54,7 @@ impl NyashBox for HttpClientBox {
     }
 
     fn to_string_box(&self) -> StringBox {
-        StringBox::new(format!("HttpClientBox(id: {})", self.id))
+        StringBox::new(format!("HttpClientBox(id: {})", self.base.id()))
     }
 
     fn as_any(&self) -> &dyn Any {
@@ -68,15 +65,28 @@ impl NyashBox for HttpClientBox {
         "HttpClientBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_http) = other.as_any().downcast_ref::<HttpClientBox>() {
-            BoolBox::new(self.id == other_http.id)
+            BoolBox::new(self.base.id() == other_http.base.id())
         } else {
             BoolBox::new(false)
         }
     }
+}
+
+impl BoxCore for HttpClientBox {
+    fn box_id(&self) -> u64 {
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "HttpClientBox(id: {})", self.base.id())
+    }
+}
+
+impl std::fmt::Display for HttpClientBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
 }
\ No newline at end of file
diff --git a/src/boxes/intent_box.rs b/src/boxes/intent_box.rs
index 3712d528..1dd52c47 100644
--- a/src/boxes/intent_box.rs
+++ b/src/boxes/intent_box.rs
@@ -25,7 +25,7 @@
  * ```
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use std::any::Any;
 use std::sync::{Arc, Mutex};
 use std::fmt::{self, Debug};
@@ -121,14 +121,14 @@ impl Transport for LocalTransport {
 /// IntentBox - 通信世界を定義
 #[derive(Clone)]
 pub struct IntentBox {
-    id: u64,
+    base: BoxBase,
     transport: Arc<Mutex<Box<dyn Transport>>>,
 }
 
 impl Debug for IntentBox {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("IntentBox")
-            .field("id", &self.id)
+            .field("id", &self.base.id())
             .field("transport", &"<Transport>")
             .finish()
     }
@@ -137,28 +137,16 @@ impl Debug for IntentBox {
 impl IntentBox {
     /// デフォルト（ローカル）通信世界を作成
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         IntentBox {
-            id,
+            base: BoxBase::new(),
             transport: Arc::new(Mutex::new(Box::new(LocalTransport::new()))),
         }
     }
     
     /// カスタムトランスポートで通信世界を作成
     pub fn new_with_transport(transport: Box<dyn Transport>) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         IntentBox {
-            id,
+            base: BoxBase::new(),
             transport: Arc::new(Mutex::new(transport)),
         }
     }
@@ -185,7 +173,7 @@ impl NyashBox for IntentBox {
     
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_intent) = other.as_any().downcast_ref::<IntentBox>() {
-            BoolBox::new(self.id == other_intent.id)
+            BoolBox::new(self.base.id() == other_intent.base.id())
         } else {
             BoolBox::new(false)
         }
@@ -203,8 +191,22 @@ impl NyashBox for IntentBox {
         self
     }
     
+}
+
+impl BoxCore for IntentBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let transport = self.transport.lock().unwrap();
+        write!(f, "IntentBox[{}]", transport.transport_type())
+    }
+}
+
+impl std::fmt::Display for IntentBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
     }
 }
 
diff --git a/src/boxes/p2p_box.rs b/src/boxes/p2p_box.rs
index d2c40bef..f2266b88 100644
--- a/src/boxes/p2p_box.rs
+++ b/src/boxes/p2p_box.rs
@@ -33,7 +33,7 @@
  * ```
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use crate::boxes::intent_box::IntentBox;
 pub use crate::boxes::intent_box::Message;
 use crate::boxes::map_box::MapBox;
@@ -47,7 +47,7 @@ pub type ListenerFn = Box<dyn NyashBox>;
 /// P2PBox内部実装
 #[derive(Debug)]
 struct P2PBoxInner {
-    id: u64,
+    base: BoxBase,
     node_id: String,
     intent_box: Arc<IntentBox>,
     listeners: Arc<Mutex<HashMap<String, Vec<ListenerFn>>>>,
@@ -62,14 +62,8 @@ pub struct P2PBox {
 impl P2PBox {
     /// 新しいP2PBoxノードを作成
     pub fn new(node_id: String, intent_box: Arc<IntentBox>) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         let inner = Arc::new(P2PBoxInner {
-            id,
+            base: BoxBase::new(),
             node_id,
             intent_box: intent_box.clone(),
             listeners: Arc::new(Mutex::new(HashMap::new())),
@@ -150,7 +144,7 @@ impl NyashBox for P2PBox {
     
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_p2p) = other.as_any().downcast_ref::<P2PBox>() {
-            BoolBox::new(self.inner.id == other_p2p.inner.id)
+            BoolBox::new(self.inner.base.id() == other_p2p.inner.base.id())
         } else {
             BoolBox::new(false)
         }
@@ -168,7 +162,20 @@ impl NyashBox for P2PBox {
         self
     }
     
+}
+
+impl BoxCore for P2PBox {
     fn box_id(&self) -> u64 {
-        self.inner.id
+        self.inner.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "P2PBox[{}]", self.inner.node_id)
+    }
+}
+
+impl std::fmt::Display for P2PBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
     }
 }
\ No newline at end of file
diff --git a/src/boxes/regex/mod.rs b/src/boxes/regex/mod.rs
index 776af813..e3f11a1d 100644
--- a/src/boxes/regex/mod.rs
+++ b/src/boxes/regex/mod.rs
@@ -3,7 +3,7 @@
 // 参考: 既存Boxの設計思想
 
 use regex::Regex;
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use crate::boxes::array::ArrayBox;
 use std::any::Any;
 use std::sync::{Arc, Mutex};
@@ -13,21 +13,16 @@ use std::fmt::Debug;
 pub struct RegexBox {
     regex: Arc<Regex>,
     pattern: Arc<String>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl RegexBox {
     pub fn new(pattern: &str) -> Result<Self, regex::Error> {
-        static mut COUNTER: u64 = 0;
         let regex = Regex::new(pattern)?;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         Ok(RegexBox {
             regex: Arc::new(regex),
             pattern: Arc::new(pattern.to_string()),
-            id,
+            base: BoxBase::new(),
         })
     }
     pub fn is_match(&self, text: &str) -> bool {
@@ -103,9 +98,6 @@ impl NyashBox for RegexBox {
         "RegexBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_regex) = other.as_any().downcast_ref::<RegexBox>() {
@@ -115,3 +107,19 @@ impl NyashBox for RegexBox {
         }
     }
 }
+
+impl BoxCore for RegexBox {
+    fn box_id(&self) -> u64 {
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "RegexBox({})", self.pattern.as_str())
+    }
+}
+
+impl std::fmt::Display for RegexBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
diff --git a/src/boxes/result/mod.rs b/src/boxes/result/mod.rs
index 615b85a9..fb7ea560 100644
--- a/src/boxes/result/mod.rs
+++ b/src/boxes/result/mod.rs
@@ -2,7 +2,7 @@
 // Nyashの箱システムによるエラー処理を提供します。
 // 参考: 既存Boxの設計思想
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore};
 use std::any::Any;
 
 #[derive(Debug)]
@@ -59,13 +59,6 @@ impl NyashBox for NyashResultBox {
         "NyashResultBox"
     }
 
-    fn box_id(&self) -> u64 {
-        // For enum variants, we use the contained value's ID
-        match self {
-            NyashResultBox::Ok(val) => val.box_id(),
-            NyashResultBox::Err(err) => err.box_id(),
-        }
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_result) = other.as_any().downcast_ref::<NyashResultBox>() {
@@ -80,6 +73,29 @@ impl NyashBox for NyashResultBox {
     }
 }
 
+impl BoxCore for NyashResultBox {
+    fn box_id(&self) -> u64 {
+        // For enum variants, we use the contained value's ID
+        match self {
+            NyashResultBox::Ok(val) => val.box_id(),
+            NyashResultBox::Err(err) => err.box_id(),
+        }
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            NyashResultBox::Ok(val) => write!(f, "Ok({})", val.to_string_box().value),
+            NyashResultBox::Err(err) => write!(f, "Err({})", err.to_string_box().value),
+        }
+    }
+}
+
+impl std::fmt::Display for NyashResultBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 // Export NyashResultBox as ResultBox for compatibility
 pub type ResultBox = NyashResultBox;
 
diff --git a/src/boxes/stream/mod.rs b/src/boxes/stream/mod.rs
index 356e5216..ac598c36 100644
--- a/src/boxes/stream/mod.rs
+++ b/src/boxes/stream/mod.rs
@@ -2,7 +2,7 @@
 // Nyashの箱システムによるストリーミング処理を提供します。
 // 参考: 既存Boxの設計思想
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox, IntegerBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, IntegerBox, BoxCore, BoxBase};
 use crate::boxes::buffer::BufferBox;
 use crate::boxes::array::ArrayBox;
 use std::any::Any;
@@ -13,33 +13,23 @@ use std::io::{Read, Write, Result};
 pub struct NyashStreamBox {
     buffer: Arc<Mutex<Vec<u8>>>,
     position: Arc<Mutex<usize>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl NyashStreamBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         NyashStreamBox {
             buffer: Arc::new(Mutex::new(Vec::new())),
             position: Arc::new(Mutex::new(0)),
-            id,
+            base: BoxBase::new(),
         }
     }
     
     pub fn from_data(data: Vec<u8>) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         NyashStreamBox {
             buffer: Arc::new(Mutex::new(data)),
             position: Arc::new(Mutex::new(0)),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -165,9 +155,6 @@ impl NyashBox for NyashStreamBox {
         "NyashStreamBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_stream) = other.as_any().downcast_ref::<NyashStreamBox>() {
@@ -182,5 +169,23 @@ impl NyashBox for NyashStreamBox {
     }
 }
 
+impl BoxCore for NyashStreamBox {
+    fn box_id(&self) -> u64 {
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let buffer = self.buffer.lock().unwrap();
+        let position = self.position.lock().unwrap();
+        write!(f, "NyashStreamBox({} bytes, pos: {})", buffer.len(), *position)
+    }
+}
+
+impl std::fmt::Display for NyashStreamBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 // Export NyashStreamBox as StreamBox for consistency
 pub type StreamBox = NyashStreamBox;
diff --git a/src/channel_box.rs b/src/channel_box.rs
index 0aa4a211..1e34e151 100644
--- a/src/channel_box.rs
+++ b/src/channel_box.rs
@@ -5,7 +5,7 @@
  * Everything is Box哲学に基づくP2P通信システム
  */
 
-use crate::box_trait::{NyashBox, StringBox, VoidBox};
+use crate::box_trait::{NyashBox, StringBox, VoidBox, BoxCore, BoxBase};
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex, Weak};
 use std::fmt::{Debug, Display};
@@ -26,25 +26,19 @@ pub struct ChannelBox {
     /// メッセージハンドラー
     handlers: Arc<Mutex<HashMap<String, Box<dyn Fn(Box<dyn NyashBox>) -> Box<dyn NyashBox> + Send>>>>,
     
-    /// チャンネルID
-    id: u64,
+    /// Box基底
+    base: BoxBase,
 }
 
 impl ChannelBox {
     /// 新しいチャンネルを作成
     pub fn new(sender: &str, receiver: &str) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         Self {
             sender_name: sender.to_string(),
             receiver_name: receiver.to_string(),
             linked_boxes: Arc::new(Mutex::new(HashMap::new())),
             handlers: Arc::new(Mutex::new(HashMap::new())),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -141,14 +135,21 @@ impl NyashBox for ChannelBox {
         self
     }
     
+}
+
+impl BoxCore for ChannelBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Channel({} >> {})", self.sender_name, self.receiver_name)
     }
 }
 
 impl Display for ChannelBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.to_string_box().value)
+        self.fmt_box(f)
     }
 }
 
@@ -157,7 +158,7 @@ impl Debug for ChannelBox {
         f.debug_struct("ChannelBox")
             .field("sender_name", &self.sender_name)
             .field("receiver_name", &self.receiver_name)
-            .field("id", &self.id)
+            .field("id", &self.base.id())
             .finish()
     }
 }
@@ -167,21 +168,15 @@ impl Debug for ChannelBox {
 pub struct MessageBox {
     pub sender: String,
     pub content: String,
-    pub timestamp: u64,
+    base: BoxBase,
 }
 
 impl MessageBox {
     pub fn new(sender: &str, content: &str) -> Self {
-        static mut COUNTER: u64 = 0;
-        let timestamp = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         Self {
             sender: sender.to_string(),
             content: content.to_string(),
-            timestamp,
+            base: BoxBase::new(),
         }
     }
 }
@@ -192,7 +187,7 @@ impl NyashBox for MessageBox {
     }
     
     fn to_string_box(&self) -> StringBox {
-        StringBox::new(&format!("[{}] {}: {}", self.timestamp, self.sender, self.content))
+        StringBox::new(&format!("[{}] {}: {}", self.base.id(), self.sender, self.content))
     }
     
     fn clone_box(&self) -> Box<dyn NyashBox> {
@@ -214,13 +209,20 @@ impl NyashBox for MessageBox {
         self
     }
     
+}
+
+impl BoxCore for MessageBox {
     fn box_id(&self) -> u64 {
-        self.timestamp
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "[{}] {}: {}", self.base.id(), self.sender, self.content)
     }
 }
 
 impl Display for MessageBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.to_string_box().value)
+        self.fmt_box(f)
     }
 }
\ No newline at end of file
diff --git a/src/exception_box.rs b/src/exception_box.rs
index 12cd4053..e0f12f5f 100644
--- a/src/exception_box.rs
+++ b/src/exception_box.rs
@@ -4,7 +4,7 @@
  * Everything is Box哲学に基づく例外システム
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use std::any::Any;
 use std::collections::HashMap;
 
@@ -14,35 +14,25 @@ pub struct ErrorBox {
     pub message: String,
     pub stack_trace: Vec<String>,
     pub cause: Option<Box<ErrorBox>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl ErrorBox {
     pub fn new(message: &str) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         Self {
             message: message.to_string(),
             stack_trace: Vec::new(),
             cause: None,
-            id,
+            base: BoxBase::new(),
         }
     }
     
     pub fn with_cause(message: &str, cause: ErrorBox) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         Self {
             message: message.to_string(),
             stack_trace: Vec::new(),
             cause: Some(Box::new(cause)),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -68,9 +58,6 @@ impl NyashBox for ErrorBox {
         StringBox::new(format!("ErrorBox({})", self.message))
     }
     
-    fn box_id(&self) -> u64 {
-        self.id
-    }
     
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_error) = other.as_any().downcast_ref::<ErrorBox>() {
@@ -89,6 +76,22 @@ impl NyashBox for ErrorBox {
     }
 }
 
+impl BoxCore for ErrorBox {
+    fn box_id(&self) -> u64 {
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "ErrorBox({})", self.message)
+    }
+}
+
+impl std::fmt::Display for ErrorBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 /// 例外タイプの判定ユーティリティ
 pub fn is_exception_type(exception: &dyn NyashBox, type_name: &str) -> bool {
     match type_name {
diff --git a/src/instance.rs b/src/instance.rs
index 1b98227e..2df5bbe2 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -5,7 +5,7 @@
  * Everything is Box哲学に基づくオブジェクト指向システム
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox, VoidBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, VoidBox, BoxCore, BoxBase};
 use crate::ast::ASTNode;
 use std::collections::HashMap;
 use std::fmt::{Debug, Display};
@@ -24,8 +24,8 @@ pub struct InstanceBox {
     /// メソッド定義（ClassBoxから共有）
     pub methods: Arc<HashMap<String, ASTNode>>,
     
-    /// インスタンスID
-    id: u64,
+    /// Box基底
+    base: BoxBase,
     
     /// 解放済みフラグ
     finalized: Arc<Mutex<bool>>,
@@ -33,12 +33,6 @@ pub struct InstanceBox {
 
 impl InstanceBox {
     pub fn new(class_name: String, fields: Vec<String>, methods: HashMap<String, ASTNode>) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         // フィールドをVoidBoxで初期化
         let mut field_map = HashMap::new();
         for field in fields {
@@ -49,7 +43,7 @@ impl InstanceBox {
             class_name,
             fields: Arc::new(Mutex::new(field_map)),
             methods: Arc::new(methods),
-            id,
+            base: BoxBase::new(),
             finalized: Arc::new(Mutex::new(false)),
         }
     }
@@ -143,13 +137,13 @@ impl InstanceBox {
 
 impl NyashBox for InstanceBox {
     fn to_string_box(&self) -> StringBox {
-        StringBox::new(format!("<{} instance #{}>", self.class_name, self.id))
+        StringBox::new(format!("<{} instance #{}>", self.class_name, self.base.id()))
     }
     
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_instance) = other.as_any().downcast_ref::<InstanceBox>() {
             // 同じインスタンスIDなら等しい
-            BoolBox::new(self.id == other_instance.id)
+            BoolBox::new(self.base.id() == other_instance.base.id())
         } else {
             BoolBox::new(false)
         }
@@ -168,14 +162,21 @@ impl NyashBox for InstanceBox {
         self
     }
     
+}
+
+impl BoxCore for InstanceBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "<{} instance #{}>", self.class_name, self.base.id())
     }
 }
 
 impl Display for InstanceBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "<{} instance>", self.class_name)
+        self.fmt_box(f)
     }
 }
 
diff --git a/src/method_box.rs b/src/method_box.rs
index bc8354d1..1b4b9533 100644
--- a/src/method_box.rs
+++ b/src/method_box.rs
@@ -5,7 +5,7 @@
  * ChatGPT先生のアドバイスを全面採用
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use crate::ast::ASTNode;
 use crate::instance::InstanceBox;
 use std::fmt::{Debug, Display};
@@ -46,19 +46,13 @@ pub struct MethodBox {
     /// メソッド定義（キャッシュ用）
     pub method_def: Option<FunctionDefinition>,
     
-    /// ユニークID
-    id: u64,
+    /// Box基底
+    base: BoxBase,
 }
 
 impl MethodBox {
     /// 新しいMethodBoxを作成
     pub fn new(instance: Box<dyn NyashBox>, method_name: String) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         // メソッド定義をキャッシュ（可能であれば）
         let method_def = if let Some(inst) = instance.as_any().downcast_ref::<InstanceBox>() {
             inst.get_method(&method_name).and_then(|ast| {
@@ -81,7 +75,7 @@ impl MethodBox {
             instance: Arc::new(Mutex::new(instance)),
             method_name,
             method_def,
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -129,14 +123,21 @@ impl NyashBox for MethodBox {
         self
     }
     
+}
+
+impl BoxCore for MethodBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "<MethodBox: {}>", self.method_name)
     }
 }
 
 impl Display for MethodBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "<MethodBox: {}>", self.method_name)
+        self.fmt_box(f)
     }
 }
 
diff --git a/src/type_box.rs b/src/type_box.rs
index f0c400dc..a5c473e9 100644
--- a/src/type_box.rs
+++ b/src/type_box.rs
@@ -5,7 +5,7 @@
  * ジェネリクス基盤を提供する革命的システム
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use std::collections::HashMap;
 use std::sync::Arc;
 use std::fmt::{Debug, Display};
@@ -72,19 +72,13 @@ pub struct TypeBox {
     /// ビルトイン型かどうか
     pub is_builtin: bool,
     
-    /// ユニークID
-    id: u64,
+    /// Box基底
+    base: BoxBase,
 }
 
 impl TypeBox {
     /// 新しいTypeBoxを作成
     pub fn new(name: &str) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         Self {
             name: name.to_string(),
             fields: HashMap::new(),
@@ -93,7 +87,7 @@ impl TypeBox {
             type_parameters: Vec::new(),
             concrete_types: HashMap::new(),
             is_builtin: false,
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -264,14 +258,21 @@ impl NyashBox for TypeBox {
         self
     }
     
+}
+
+impl BoxCore for TypeBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id()
+    }
+
+    fn fmt_box(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "<TypeBox: {}>", self.full_name())
     }
 }
 
 impl Display for TypeBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "<TypeBox: {}>", self.full_name())
+        self.fmt_box(f)
     }
 }