diff --git a/build.gradle.kts b/build.gradle.kts
index 14ec35d..fc891f2 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -9,7 +9,7 @@ plugins {
 }
 
 group = "net.azisaba"
-version = "1.15.2+6.16.4"
+version = "1.15.2+6.16.5"
 
 java {
     toolchain.languageVersion.set(JavaLanguageVersion.of(8))
diff --git a/src/main/java/com/github/mori01231/lifecore/LifeCore.kt b/src/main/java/com/github/mori01231/lifecore/LifeCore.kt
index bc121c5..a563384 100644
--- a/src/main/java/com/github/mori01231/lifecore/LifeCore.kt
+++ b/src/main/java/com/github/mori01231/lifecore/LifeCore.kt
@@ -20,14 +20,11 @@ import org.bukkit.Bukkit
 import org.bukkit.command.CommandExecutor
 import org.bukkit.entity.ItemFrame
 import org.bukkit.plugin.java.JavaPlugin
-import org.bukkit.plugin.java.PluginClassLoader
 import java.io.File
 import java.io.IOException
 import java.net.InetSocketAddress
-import java.nio.file.Files
 import java.util.concurrent.Executor
 import java.util.concurrent.Executors
-import java.util.stream.Collectors
 
 class LifeCore : JavaPlugin() {
     val gcListener = GCListener(this)
@@ -308,6 +305,7 @@ class LifeCore : JavaPlugin() {
         pm.registerEvents(UpdateInventoryOnCloseListener(this), this)
         pm.registerEvents(PromptSignListener, this)
         pm.registerEvents(PicksawItemListener(dataLoader), this)
+        pm.registerEvents(BlockListener, this)
 
         // Items
         pm.registerEvents(OreOnlyItemListener(), this)
diff --git a/src/main/java/com/github/mori01231/lifecore/command/BlockListener.kt b/src/main/java/com/github/mori01231/lifecore/command/BlockListener.kt
new file mode 100644
index 0000000..0c0803a
--- /dev/null
+++ b/src/main/java/com/github/mori01231/lifecore/command/BlockListener.kt
@@ -0,0 +1,17 @@
+package com.github.mori01231.lifecore.command
+
+import com.github.mori01231.lifecore.util.ItemUtil
+import org.bukkit.ChatColor
+import org.bukkit.event.EventHandler
+import org.bukkit.event.Listener
+import org.bukkit.event.block.BlockPlaceEvent
+
+object BlockListener : Listener {
+    @EventHandler
+    fun onBlockPlace(e: BlockPlaceEvent) {
+        if (ItemUtil.containsTag(e.itemInHand, "backup") && !e.player.isSneaking) {
+            e.player.sendMessage("${ChatColor.RED}このブロックを設置すると中身のアイテムが変質し、元の状態に戻らなくなる可能性があります。")
+            e.player.sendMessage("${ChatColor.RED}この警告を無視して設置したい場合はスニークしながら設置してください。")
+        }
+    }
+}
diff --git a/src/main/java/com/github/mori01231/lifecore/util/ItemUtil.java b/src/main/java/com/github/mori01231/lifecore/util/ItemUtil.java
index ad0da1e..bcaa6c1 100644
--- a/src/main/java/com/github/mori01231/lifecore/util/ItemUtil.java
+++ b/src/main/java/com/github/mori01231/lifecore/util/ItemUtil.java
@@ -159,4 +159,10 @@ public static ItemStack restoreTag(@Nullable ItemStack stack) {
         if (backup == null || backup.isEmpty()) return stack;
         return setTag(stack, null, backup);
     }
+
+    public static boolean containsTag(@Nullable ItemStack stack, @NotNull String key) {
+        if (stack == null || stack.getType().isAir()) return false;
+        NBTTagCompound tag = CraftItemStack.asNMSCopy(stack).getTag();
+        return tag != null && tag.hasKey(key);
+    }
 }