diff --git a/src/Data/Bits/ToolsYj.hs b/src/Data/Bits/ToolsYj.hs
--- a/src/Data/Bits/ToolsYj.hs
+++ b/src/Data/Bits/ToolsYj.hs
@@ -1,7 +1,13 @@
 {-# OPTIONS_GHC -Wall -fno-warn-tabs #-}
 
-module Data.Bits.ToolsYj (bitsToBits, checkBits, bitsList) where
+module Data.Bits.ToolsYj (
 
+	bitsToBits, checkBits, bitsList,
+
+	popBit
+
+	) where
+
 import Control.Arrow
 import Data.Bits
 
@@ -15,3 +21,6 @@
 bitsToBits :: (Bits a, Bits b) => Int -> a -> b
 bitsToBits n b = foldl setBit zeroBits
 	. map fst . filter snd $ map (id &&& testBit b) [0 .. n - 1]
+
+popBit :: Bits b => b -> (Bool, b)
+popBit n = (n `testBit` 0, n `shiftR` 1)
diff --git a/tools-yj.cabal b/tools-yj.cabal
--- a/tools-yj.cabal
+++ b/tools-yj.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           tools-yj
-version:        0.1.0.31
+version:        0.1.0.32
 synopsis:       Tribial tools
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/tools-yj#readme>
 category:       Tools