diff --git a/src/boxes/buffer/mod.rs b/src/boxes/buffer/mod.rs
index f4421564..59f1dcf8 100644
--- a/src/boxes/buffer/mod.rs
+++ b/src/boxes/buffer/mod.rs
@@ -28,7 +28,7 @@
  * ```
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox, IntegerBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, IntegerBox, BoxCore, BoxBase};
 use crate::boxes::array::ArrayBox;
 use std::any::Any;
 use std::sync::{Arc, Mutex};
@@ -37,31 +37,21 @@ use std::fmt::{Debug, Display};
 #[derive(Debug, Clone)]
 pub struct BufferBox {
     data: Arc<Mutex<Vec<u8>>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl BufferBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         BufferBox { 
             data: Arc::new(Mutex::new(Vec::new())),
-            id,
+            base: BoxBase::new(),
         }
     }
     
     pub fn from_vec(data: Vec<u8>) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         BufferBox { 
             data: Arc::new(Mutex::new(data)),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -158,6 +148,23 @@ impl BufferBox {
     }
 }
 
+impl BoxCore for BufferBox {
+    fn box_id(&self) -> u64 {
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let data = self.data.lock().unwrap();
+        write!(f, "BufferBox({} bytes)", data.len())
+    }
+}
+
+impl Display for BufferBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 impl NyashBox for BufferBox {
     fn clone_box(&self) -> Box<dyn NyashBox> {
         Box::new(self.clone())
@@ -176,9 +183,6 @@ impl NyashBox for BufferBox {
         "BufferBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_buffer) = other.as_any().downcast_ref::<BufferBox>() {
diff --git a/src/boxes/egui_box.rs b/src/boxes/egui_box.rs
index 5ed07444..27e689da 100644
--- a/src/boxes/egui_box.rs
+++ b/src/boxes/egui_box.rs
@@ -31,7 +31,7 @@
  * - `run()`はブロッキング動作（アプリ終了まで制御を返さない）
  */
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, BoolBox, BoxCore, BoxBase};
 use crate::interpreter::RuntimeError;
 use std::any::Any;
 use std::sync::{Arc, Mutex};
@@ -47,6 +47,7 @@ use eframe::{self, epaint::Vec2};
 /// app.run()
 /// ```
 pub struct EguiBox {
+    base: BoxBase,
     title: String,
     size: Vec2,
     app_state: Arc<Mutex<Box<dyn Any + Send>>>,
@@ -65,6 +66,7 @@ impl std::fmt::Debug for EguiBox {
 impl EguiBox {
     pub fn new() -> Self {
         Self {
+            base: BoxBase::new(),
             title: "Nyash GUI Application".to_string(),
             size: Vec2::new(800.0, 600.0),
             app_state: Arc::new(Mutex::new(Box::new(()) as Box<dyn Any + Send>)),
@@ -100,6 +102,22 @@ impl eframe::App for NyashApp {
     }
 }
 
+impl BoxCore for EguiBox {
+    fn box_id(&self) -> u64 {
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "EguiBox('{}', {}x{})", self.title, self.size.x, self.size.y)
+    }
+}
+
+impl std::fmt::Display for EguiBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 impl NyashBox for EguiBox {
     fn to_string_box(&self) -> StringBox {
         StringBox::new(
@@ -110,6 +128,7 @@ impl NyashBox for EguiBox {
     fn clone_box(&self) -> Box<dyn NyashBox> {
         // GUI Boxはクローン不可（単一インスタンス）
         Box::new(Self {
+            base: BoxBase::new(),
             title: self.title.clone(),
             size: self.size,
             app_state: Arc::new(Mutex::new(Box::new(()) as Box<dyn Any + Send>)),
@@ -133,10 +152,6 @@ impl NyashBox for EguiBox {
         "EguiBox"
     }
     
-    fn box_id(&self) -> u64 {
-        // 簡易的なIDとしてポインタアドレスを使用
-        self as *const _ as u64
-    }
 }
 
 // EguiBoxのメソッド実装（実際にはインタープリターから呼ばれない）
diff --git a/src/boxes/file/mod.rs b/src/boxes/file/mod.rs
index a71aef2f..e933bd9a 100644
--- a/src/boxes/file/mod.rs
+++ b/src/boxes/file/mod.rs
@@ -2,7 +2,7 @@
 // Nyashの箱システムによるファイル入出力を提供します。
 // 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::fs::{File, OpenOptions};
 use std::io::{Read, Write, Result};
@@ -12,21 +12,16 @@ use std::sync::{Arc, Mutex};
 pub struct FileBox {
     file: Arc<Mutex<File>>,
     path: Arc<String>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl FileBox {
     pub fn open(path: &str) -> Result<Self> {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         let file = OpenOptions::new().read(true).write(true).create(true).open(path)?;
         Ok(FileBox { 
             file: Arc::new(Mutex::new(file)),
             path: Arc::new(path.to_string()),
-            id,
+            base: BoxBase::new(),
         })
     }
     
@@ -82,6 +77,16 @@ impl FileBox {
     }
 }
 
+impl BoxCore for FileBox {
+    fn box_id(&self) -> u64 {
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "FileBox({})", self.path)
+    }
+}
+
 impl NyashBox for FileBox {
     fn clone_box(&self) -> Box<dyn NyashBox> {
         // Note: Cannot truly clone a File handle, so create a new one to the same path
@@ -103,9 +108,6 @@ impl NyashBox for FileBox {
         "FileBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_file) = other.as_any().downcast_ref::<FileBox>() {
@@ -115,3 +117,9 @@ impl NyashBox for FileBox {
         }
     }
 }
+
+impl std::fmt::Display for FileBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
diff --git a/src/boxes/json/mod.rs b/src/boxes/json/mod.rs
index cd2ee1a8..10803868 100644
--- a/src/boxes/json/mod.rs
+++ b/src/boxes/json/mod.rs
@@ -2,7 +2,7 @@
 // Nyashの箱システムによるJSON解析・生成を提供します。
 // 参考: 既存Boxの設計思想
 
-use crate::box_trait::{NyashBox, StringBox, BoolBox, IntegerBox};
+use crate::box_trait::{NyashBox, BoxCore, BoxBase, StringBox, BoolBox, IntegerBox};
 use crate::boxes::array::ArrayBox;
 use crate::boxes::map_box::MapBox;
 use std::any::Any;
@@ -12,32 +12,22 @@ use serde_json::{Value, Error};
 #[derive(Debug, Clone)]
 pub struct JSONBox {
     value: Arc<Mutex<Value>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl JSONBox {
     pub fn from_str(s: &str) -> Result<Self, Error> {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         let value = serde_json::from_str(s)?;
         Ok(JSONBox { 
             value: Arc::new(Mutex::new(value)), 
-            id 
+            base: BoxBase::new() 
         })
     }
     
     pub fn new(value: Value) -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
         JSONBox { 
             value: Arc::new(Mutex::new(value)), 
-            id 
+            base: BoxBase::new() 
         }
     }
     
@@ -129,6 +119,35 @@ impl JSONBox {
     }
 }
 
+impl BoxCore for JSONBox {
+    fn box_id(&self) -> u64 {
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let value = self.value.lock().unwrap();
+        let json_type = match *value {
+            Value::Null => "null",
+            Value::Bool(_) => "boolean",
+            Value::Number(_) => "number",
+            Value::String(_) => "string",
+            Value::Array(ref arr) => {
+                return write!(f, "JSONBox[array:{}]", arr.len());
+            },
+            Value::Object(ref obj) => {
+                return write!(f, "JSONBox[object:{}]", obj.len());
+            },
+        };
+        write!(f, "JSONBox[{}]", json_type)
+    }
+}
+
+impl std::fmt::Display for JSONBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        self.fmt_box(f)
+    }
+}
+
 impl NyashBox for JSONBox {
     fn clone_box(&self) -> Box<dyn NyashBox> {
         Box::new(self.clone())
@@ -147,9 +166,6 @@ impl NyashBox for JSONBox {
         "JSONBox"
     }
 
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_json) = other.as_any().downcast_ref::<JSONBox>() {
diff --git a/src/boxes/map_box.rs b/src/boxes/map_box.rs
index 87b7f7c6..6dfd80fe 100644
--- a/src/boxes/map_box.rs
+++ b/src/boxes/map_box.rs
@@ -103,7 +103,7 @@
  * - 存在しないキーの取得は "Key not found" メッセージ返却
  */
 
-use crate::box_trait::{NyashBox, StringBox, IntegerBox, BoolBox};
+use crate::box_trait::{BoxCore, BoxBase, NyashBox, StringBox, IntegerBox, BoolBox};
 use crate::boxes::array::ArrayBox;
 use std::fmt::{Debug, Display};
 use std::any::Any;
@@ -114,20 +114,14 @@ use std::sync::{Arc, Mutex};
 #[derive(Clone)]
 pub struct MapBox {
     data: Arc<Mutex<HashMap<String, Box<dyn NyashBox>>>>,
-    id: u64,
+    base: BoxBase,
 }
 
 impl MapBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
         Self {
             data: Arc::new(Mutex::new(HashMap::new())),
-            id,
+            base: BoxBase::new(),
         }
     }
     
@@ -229,6 +223,17 @@ impl MapBox {
     }
 }
 
+impl BoxCore for MapBox {
+    fn box_id(&self) -> u64 {
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let size = self.data.lock().unwrap().len();
+        write!(f, "MapBox(size={})", size)
+    }
+}
+
 impl NyashBox for MapBox {
     fn type_name(&self) -> &'static str {
         "MapBox"
@@ -246,7 +251,7 @@ impl NyashBox for MapBox {
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_map) = other.as_any().downcast_ref::<MapBox>() {
             // 同じインスタンスかチェック（データの共有を考慮）
-            BoolBox::new(self.id == other_map.id)
+            BoolBox::new(self.box_id() == other_map.box_id())
         } else {
             BoolBox::new(false)
         }
@@ -255,15 +260,11 @@ impl NyashBox for MapBox {
     fn as_any(&self) -> &dyn Any {
         self
     }
-    
-    fn box_id(&self) -> u64 {
-        self.id
-    }
 }
 
 impl Display for MapBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.to_string_box().value)
+        self.fmt_box(f)
     }
 }
 
@@ -271,7 +272,7 @@ impl Debug for MapBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let data = self.data.lock().unwrap();
         f.debug_struct("MapBox")
-            .field("id", &self.id)
+            .field("id", &self.base.id)
             .field("size", &data.len())
             .field("keys", &data.keys().collect::<Vec<_>>())
             .finish()
diff --git a/src/boxes/sound_box.rs b/src/boxes/sound_box.rs
index 8f999dc5..ceaa85da 100644
--- a/src/boxes/sound_box.rs
+++ b/src/boxes/sound_box.rs
@@ -138,7 +138,7 @@
  * - Web環境では制限が多い（ユーザー操作後のみ音声再生可能）
  */
 
-use crate::box_trait::{NyashBox, StringBox, IntegerBox, BoolBox};
+use crate::box_trait::{NyashBox, StringBox, IntegerBox, BoolBox, BoxCore, BoxBase};
 use std::fmt::{Debug, Display};
 use std::any::Any;
 use std::process::Command;
@@ -147,18 +147,14 @@ use std::time::Duration;
 /// 音響効果を提供するBox
 #[derive(Debug, Clone)]
 pub struct SoundBox {
-    id: u64,
+    base: BoxBase,
 }
 
 impl SoundBox {
     pub fn new() -> Self {
-        static mut COUNTER: u64 = 0;
-        let id = unsafe {
-            COUNTER += 1;
-            COUNTER
-        };
-        
-        Self { id }
+        Self { 
+            base: BoxBase::new() 
+        }
     }
     
     /// ビープ音を鳴らす（基本）
@@ -332,7 +328,7 @@ impl NyashBox for SoundBox {
     
     fn equals(&self, other: &dyn NyashBox) -> BoolBox {
         if let Some(other_sound) = other.as_any().downcast_ref::<SoundBox>() {
-            BoolBox::new(self.id == other_sound.id)
+            BoolBox::new(self.base.id == other_sound.base.id)
         } else {
             BoolBox::new(false)
         }
@@ -342,13 +338,20 @@ impl NyashBox for SoundBox {
         self
     }
     
+}
+
+impl BoxCore for SoundBox {
     fn box_id(&self) -> u64 {
-        self.id
+        self.base.id
+    }
+    
+    fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "SoundBox()")
     }
 }
 
 impl Display for SoundBox {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "SoundBox()")
+        self.fmt_box(f)
     }
 }
\ No newline at end of file