diff -ur --strip-trailing-cr piwik.orig/core/Common.php piwik/core/Common.php
--- piwik.orig/core/Common.php	2016-05-23 11:15:11.000000000 +0900
+++ piwik/core/Common.php	2016-08-13 15:13:40.930493900 +0900
@@ -14,6 +14,7 @@
 use Piwik\Intl\Data\Provider\RegionDataProvider;
 use Piwik\Plugins\UserCountry\LocationProvider\DefaultProvider;
 use Piwik\Tracker\Cache as TrackerCache;
+use Piwik\Plugins\Referrers\SearchEngine;
 
 /**
  * Contains helper methods used by both Piwik Core and the Piwik Tracking engine.
@@ -322,6 +323,7 @@
         // $_GET and $_REQUEST already urldecode()'d
         // decode
         // note: before php 5.2.7, htmlspecialchars() double encodes &#x hex items
+        $value = SearchEngine::getInstance()->convertCharsetByDefault($value);
         $value = html_entity_decode($value, self::HTML_ENCODING_QUOTE_STYLE, 'UTF-8');
 
         $value = self::sanitizeNullBytes($value);
diff -ur --strip-trailing-cr piwik.orig/core/Tracker/PageUrl.php piwik/core/Tracker/PageUrl.php
--- piwik.orig/core/Tracker/PageUrl.php	2016-04-01 10:07:54.000000000 +0900
+++ piwik/core/Tracker/PageUrl.php	2016-08-13 15:13:40.930493900 +0900
@@ -216,6 +216,33 @@
         return $originalUrl;
     }
 
+    /*
+     * Detect UTF-8, which mysql understands.
+     *
+     * @param string $string The string being detected.
+     * @return boolean
+     */
+    private static function isValidUtf8($string)
+    {
+        // Reference: http://tools.ietf.org/html/rfc3629
+        $regex = '/(?:'
+            . '[\x00-\x7f]|'                                    // U+0000   - U+007F
+            . '[\xc2-\xdf][\x80-\xbf]|'                         // U+0080   - U+07FF
+            . '\xe0[\xa0-\xbf][\x80-\xbf]|'                     // U+0800   - U+0FFF
+            . '[\xe1-\xec][\x80-\xbf][\x80-\xbf]|'              // U+1000   - U+CFFF
+            . '\xed[\x80-\x9f][\x80-\xbf]|'                     // U+D000   - U+D7FF
+            . '[\xee-\xef][\x80-\xbf][\x80-\xbf]|'              // U+E000   - U+FFFF
+            #   . '\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|'          // U+10000  - U+3FFFF perhaps, mysql does not understand.
+            #   . '[\xf1-\xf3][\x80-\xbf][\x80-\xbf][\x80-\xbf]|'   // U+40000  - U+FFFFF perhaps, mysql does not understand.
+            #   . '\xf4[\x80-\x8f][\x80-\xbf][\x80-\xbf]|'          // U+100000 - U+10FFFF perhaps, mysql does not understand.
+            . ')/';
+        $result = preg_replace($regex, '', $string);
+        if ($result !== '') {
+            return FALSE;
+        }
+        return TRUE;
+    }
+
     /**
      * Clean up string contents (filter, truncate, ...)
      *
@@ -224,11 +251,14 @@
      */
     public static function cleanupString($string)
     {
+        if (!PageUrl::isValidUtf8($string)) {
+            $string = '';
+        }
         $string = trim($string);
         $string = str_replace(array("\n", "\r", "\0"), '', $string);
 
         $limit = Config::getInstance()->Tracker['page_maximum_length'];
-        $clean = substr($string, 0, $limit);
+        $clean = Common::mb_substr($string, 0, $limit);
         return $clean;
     }
 
diff -ur --strip-trailing-cr piwik.orig/plugins/Referrers/SearchEngine.php piwik/plugins/Referrers/SearchEngine.php
--- piwik.orig/plugins/Referrers/SearchEngine.php	2016-07-14 10:48:53.000000000 +0900
+++ piwik/plugins/Referrers/SearchEngine.php	2016-08-13 15:13:40.930493900 +0900
@@ -24,6 +24,7 @@
 
     /** @var string location of definition file (relative to PIWIK_INCLUDE_PATH) */
     const DEFINITION_FILE = '/vendor/piwik/searchengine-and-social-list/SearchEngines.yml';
+    const DEFAULT_CHARSETS_BY_HOST = 'search.yahoo.co.jp';
 
     protected $definitionList = null;
 
@@ -388,6 +389,23 @@
         return $host;
     }
 
+    private function getDefaultCharsets()
+    {
+        $searchEngine = $this->getDefinitionByHost(SearchEngine::DEFAULT_CHARSETS_BY_HOST);
+        $charsets = array();
+        if (!empty($searchEngine) and !empty($searchEngine['charsets'])) {
+            $charsets = $searchEngine['charsets'];
+        }
+        return($charsets);
+    }
+
+    public function convertCharsetByDefault($string)
+    {
+        $charsets = $this->getDefaultCharsets();
+        $string = $this->convertCharset($string, $charsets);
+        return($string);
+    }
+
     /**
      * Tries to convert the given string from one of the given charsets to UTF-8
      * @param string $string
@@ -396,6 +414,9 @@
      */
     protected function convertCharset($string, $charsets)
     {
+        if (empty($charsets)) {
+            $charsets = $this->getDefaultCharsets();
+        }
         if (function_exists('iconv')
             && !empty($charsets)
         ) {
diff -ur --strip-trailing-cr piwik.orig/vendor/piwik/searchengine-and-social-list/SearchEngines.yml piwik/vendor/piwik/searchengine-and-social-list/SearchEngines.yml
--- piwik.orig/vendor/piwik/searchengine-and-social-list/SearchEngines.yml	2016-07-14 02:20:30.000000000 +0900
+++ piwik/vendor/piwik/searchengine-and-social-list/SearchEngines.yml	2016-08-13 15:19:12.434500740 +0900
@@ -8,6 +8,15 @@
     backlink: 's/{k}'
     charsets:
       - iso-8859-2
+118 700:
+  - 
+    urls:
+      - www.118700.se
+      - foretag.118700.se
+      - webben.118700.se
+    params:
+      - q
+    backlink: 'sok.aspx?q={k}'
 123people:
   - 
     urls:
@@ -74,6 +83,13 @@
     params:
       - q
     backlink: 's.py?q={k}'
+Allaverksamheter:
+  - 
+    urls:
+      - www.allaverksamheter.se
+    params:
+      - What
+    backlink: 'SearchResult.aspx?What={k}'
 Alexa:
   - 
     urls:
@@ -265,6 +281,10 @@
     params:
       - q
     backlink: '?q={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
 auone Images:
   - 
     urls:
@@ -272,6 +292,10 @@
     params:
       - q
     backlink: '?q={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
 Austronaut:
   - 
     urls:
@@ -319,6 +343,10 @@
     params:
       - q
     backlink: 'cgi-bin/search-st?q={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
 Biglobe Images:
   - 
     urls:
@@ -1230,6 +1258,13 @@
     params:
       - q
     backlink: 'szukaj?q={k}'
+Isodelen:
+  - 
+    urls:
+      - www.isodelen.se
+    params:
+      - Keywords
+    backlink: 'sokresultat?Keywords={k}'
 Ixquick:
   - 
     urls:
@@ -1650,6 +1685,13 @@
       - query
       - words
     backlink: 'search?query={k}'
+Riksdelen:
+  - 
+    urls:
+      - www.riksdelen.se
+    params:
+      - What
+    backlink: 'SearchResult.aspx?What={k}'
 Road Runner:
   - 
     urls:
@@ -2245,6 +2287,10 @@
       - p
       - vp
     backlink: 'search?p={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
   -
     urls:
       - jp.hao123.com
@@ -2267,6 +2313,10 @@
     params:
       - p
     backlink: 'search?p={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
 Yahoo! Japan Videos:
   -
     urls:
@@ -2274,8 +2324,12 @@
     params:
       - p
     backlink: 'search?p={k}'
+    charsets:
+      - utf-8
+      - euc-jp
+      - ms932
 Yam:
-  - 
+  -
     urls:
       - search.yam.com
     params:
diff -ur --strip-trailing-cr piwik.orig/vendor/piwik/searchengine-and-social-list/Socials.yml piwik/vendor/piwik/searchengine-and-social-list/Socials.yml
--- piwik.orig/vendor/piwik/searchengine-and-social-list/Socials.yml	2016-07-14 02:20:30.000000000 +0900
+++ piwik/vendor/piwik/searchengine-and-social-list/Socials.yml	2016-08-13 15:19:15.001500794 +0900
@@ -216,3 +216,12 @@
 
 tumblr:
   - tumblr.com
+
+mixi:
+  - mixi.jp
+
+lang-8:
+  - lang-8.com
+
+gree:
+  - gree.jp