diff --git a/lunr.ja.js b/lunr.ja.js
new file mode 100644
index 0000000..1c3e512
--- /dev/null
+++ b/lunr.ja.js
@@ -0,0 +1,134 @@
+/*!
+ * Lunr languages, `Japanese` language
+ * https://github.com/MihaiValentin/lunr-languages
+ *
+ * Copyright 2014, Chad Liu
+ * http://www.mozilla.org/MPL/
+ */
+/*!
+ * based on
+ * Snowball JavaScript Library v0.3
+ * http://code.google.com/p/urim/
+ * http://snowball.tartarus.org/
+ *
+ * Copyright 2010, Oleg Mazko
+ * http://www.mozilla.org/MPL/
+ */
+
+/**
+ * export the module via AMD, CommonJS or as a browser global
+ * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
+ */
+ ;
+ (function(root, factory) {
+   if (typeof define === 'function' && define.amd) {
+     // AMD. Register as an anonymous module.
+     define(factory)
+   } else if (typeof exports === 'object') {
+     /**
+      * Node. Does not work with strict CommonJS, but
+      * only CommonJS-like environments that support module.exports,
+      * like Node.
+      */
+     module.exports = factory()
+   } else {
+     // Browser globals (root is window)
+     factory()(root.lunr);
+   }
+ }(this, function() {
+   /**
+    * Just return a value to define the module export.
+    * This example returns an object, but the module
+    * can return a function as the exported value.
+    */
+   return function(lunr) {
+     /* throw error if lunr is not yet included */
+     if ('undefined' === typeof lunr) {
+       throw new Error('Lunr is not present. Please include / require Lunr before this script.');
+     }
+ 
+     /* throw error if lunr stemmer support is not yet included */
+     if ('undefined' === typeof lunr.stemmerSupport) {
+       throw new Error('Lunr stemmer support is not present. Please include / require Lunr stemmer support before this script.');
+     }
+ 
+     /* register specific locale function */
+     lunr.ja = function() {
+       this.pipeline.reset();
+       this.pipeline.add(
+         lunr.ja.trimmer,
+         lunr.ja.stopWordFilter,
+         lunr.ja.stemmer
+       );
+       // change the tokenizer for japanese one
+       lunr.tokenizer = lunr.ja.tokenizer;
+     };
+     var segmenter = new TinySegmenter();  // インスタンス生成
+ 
+     lunr.ja.tokenizer = function (obj) {
+         if (!arguments.length || obj == null || obj == undefined) return []
+         if (Array.isArray(obj)) return obj.map(function (t) { return t.toLowerCase() })
+ 
+         var str = obj.toString().replace(/^\s+/, '')
+ 
+         for (var i = str.length - 1; i >= 0; i--) {
+             if (/\S/.test(str.charAt(i))) {
+                 str = str.substring(0, i + 1)
+                 break
+             }
+         }
+ 
+                      
+         var segs = segmenter.segment(str);  // 単語の配列が返る
+         return segs.filter(function (token) {
+             return !!token
+           })
+           .map(function (token) {
+             return token
+           })
+     }
+ 
+     /* lunr stemmer function */
+     lunr.ja.stemmer = (function() {
+       
+       /* TODO japanese stemmer  */
+       return function(word) {
+         return word;
+       }
+     })();
+ 
+     lunr.Pipeline.registerFunction(lunr.ja.stemmer, 'stemmer-ja');
+ 
+     /* lunr trimmer function */
+     lunr.ja.wordCharacters = "一二三四五六七八九十百千万億兆一-龠々〆ヵヶぁ-んァ-ヴーｱ-ﾝﾞa-zA-Zａ-ｚＡ-Ｚ0-9０-９";
+     lunr.ja.trimmer = lunr.trimmerSupport.generateTrimmer(lunr.ja.wordCharacters);
+     lunr.Pipeline.registerFunction(lunr.ja.trimmer, 'trimmer-ja');
+ 
+     /* stop word filter function */
+     lunr.ja.stopWordFilter = function(token) {
+       if (lunr.ja.stopWordFilter.stopWords.indexOf(token) === -1) {
+         return token;
+       }
+     };
+ 
+     lunr.ja.stopWordFilter.stopWords = new lunr.SortedSet();
+     lunr.ja.stopWordFilter.stopWords.length = 45;
+ 
+     // The space at the beginning is crucial: It marks the empty string
+     // as a stop word. lunr.js crashes during search when documents
+     // processed by the pipeline still contain the empty string.
+     // stopword for japanese is from http://www.ranks.nl/stopwords/japanese
+     lunr.ja.stopWordFilter.stopWords.elements = ' これ それ あれ この その あの ここ そこ あそこ こちら どこ だれ なに なん 何 私 貴方 貴方方 我々 私達 あの人 あのかた 彼女 彼 です あります おります います は が の に を で え から まで より も どの と し それで しかし'.split(' ');
+     lunr.Pipeline.registerFunction(lunr.ja.stopWordFilter, 'stopWordFilter-ja');
+ 
+     // alias ja => jp for backward-compatibility.
+     // jp is the country code, while ja is the language code
+     // a new lunr.ja.js has been created, but in order to
+     // keep the backward compatibility, we'll leave the lunr.jp.js
+     // here for a while, and just make it use the new lunr.ja.js
+     lunr.jp = lunr.ja;
+     lunr.Pipeline.registerFunction(lunr.jp.stemmer, 'stemmer-jp');
+     lunr.Pipeline.registerFunction(lunr.jp.trimmer, 'trimmer-jp');
+     lunr.Pipeline.registerFunction(lunr.jp.stopWordFilter, 'stopWordFilter-jp');
+   };
+ }))
\ No newline at end of file
diff --git a/lunr.jp.js b/lunr.jp.js
index 4dcdc43..73ebff1 100644
--- a/lunr.jp.js
+++ b/lunr.jp.js
@@ -1,118 +1,5 @@
-/*!
- * Lunr languages, `Japanese` language
- * https://github.com/MihaiValentin/lunr-languages
- *
- * Copyright 2014, Chad Liu
- * http://www.mozilla.org/MPL/
- */
-/*!
- * based on
- * Snowball JavaScript Library v0.3
- * http://code.google.com/p/urim/
- * http://snowball.tartarus.org/
- *
- * Copyright 2010, Oleg Mazko
- * http://www.mozilla.org/MPL/
- */
-
-/**
- * export the module via AMD, CommonJS or as a browser global
- * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
- */
-;
-(function(root, factory) {
-  if (typeof define === 'function' && define.amd) {
-    // AMD. Register as an anonymous module.
-    define(factory)
-  } else if (typeof exports === 'object') {
-    /**
-     * Node. Does not work with strict CommonJS, but
-     * only CommonJS-like environments that support module.exports,
-     * like Node.
-     */
-    module.exports = factory()
-  } else {
-    // Browser globals (root is window)
-    factory()(root.lunr);
-  }
-}(this, function() {
-  /**
-   * Just return a value to define the module export.
-   * This example returns an object, but the module
-   * can return a function as the exported value.
-   */
-  return function(lunr) {
-    /* throw error if lunr is not yet included */
-    if ('undefined' === typeof lunr) {
-      throw new Error('Lunr is not present. Please include / require Lunr before this script.');
-    }
-
-    /* throw error if lunr stemmer support is not yet included */
-    if ('undefined' === typeof lunr.stemmerSupport) {
-      throw new Error('Lunr stemmer support is not present. Please include / require Lunr stemmer support before this script.');
-    }
-
-    /* register specific locale function */
-    lunr.jp = function() {
-      this.pipeline.reset();
-      this.pipeline.add(
-        lunr.jp.stopWordFilter,
-        lunr.jp.stemmer
-      );
-      // change the tokenizer for japanese one
-      lunr.tokenizer = lunr.jp.tokenizer;
-    };
-    var segmenter = new TinySegmenter();  // インスタンス生成
-
-    lunr.jp.tokenizer = function (obj) {
-        if (!arguments.length || obj == null || obj == undefined) return []
-        if (Array.isArray(obj)) return obj.map(function (t) { return t.toLowerCase() })
-
-        var str = obj.toString().replace(/^\s+/, '')
-
-        for (var i = str.length - 1; i >= 0; i--) {
-            if (/\S/.test(str.charAt(i))) {
-                str = str.substring(0, i + 1)
-                break
-            }
-        }
-
-                     
-        var segs = segmenter.segment(str);  // 単語の配列が返る
-        return segs.filter(function (token) {
-            return !!token
-          })
-          .map(function (token) {
-            return token
-          })
-    }
-
-    /* lunr stemmer function */
-    lunr.jp.stemmer = (function() {
-      
-      /* TODO japanese stemmer  */
-      return function(word) {
-        return word;
-      }
-    })();
-
-    lunr.Pipeline.registerFunction(lunr.jp.stemmer, 'stemmer-jp');
-
-    /* stop word filter function */
-    lunr.jp.stopWordFilter = function(token) {
-      if (lunr.jp.stopWordFilter.stopWords.indexOf(token) === -1) {
-        return token;
-      }
-    };
-
-    lunr.jp.stopWordFilter.stopWords = new lunr.SortedSet();
-    lunr.jp.stopWordFilter.stopWords.length = 45;
-
-    // The space at the beginning is crucial: It marks the empty string
-    // as a stop word. lunr.js crashes during search when documents
-    // processed by the pipeline still contain the empty string.
-    // stopword for japanese is from http://www.ranks.nl/stopwords/japanese
-    lunr.jp.stopWordFilter.stopWords.elements = ' これ それ あれ この その あの ここ そこ あそこ こちら どこ だれ なに なん 何 私 貴方 貴方方 我々 私達 あの人 あのかた 彼女 彼 です あります おります います は が の に を で え から まで より も どの と し それで しかし'.split(' ');
-    lunr.Pipeline.registerFunction(lunr.jp.stopWordFilter, 'stopWordFilter-jp');
-  };
-}))
\ No newline at end of file
+// jp is the country code, while ja is the language code
+// a new lunr.ja.js has been created, but in order to
+// keep the backward compatibility, we'll leave the lunr.jp.js
+// here for a while, and just make it use the new lunr.ja.js
+module.exports = require('./lunr.ja');
\ No newline at end of file