diff --git a/Gemfile b/Gemfile
index cdc98d5e0..b6d77cf94 100644
--- a/Gemfile
+++ b/Gemfile
@@ -185,8 +185,6 @@ end
 
 gem 'rmmseg-cpp', require: false
 
-gem 'stringex', require: false
-
 gem 'logster'
 
 # perftools only works on 1.9 atm
diff --git a/Gemfile.lock b/Gemfile.lock
index a68db9f9f..f012589f5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -423,7 +423,6 @@ GEM
       activesupport (>= 3.0)
       sprockets (~> 2.8)
     stackprof (0.2.7)
-    stringex (2.5.2)
     therubyracer (0.12.2)
       libv8 (~> 3.16.14.0)
       ref
@@ -544,7 +543,6 @@ DEPENDENCIES
   sinatra
   spork-rails
   stackprof
-  stringex
   therubyracer
   thin
   timecop
diff --git a/app/assets/javascripts/discourse/models/category.js b/app/assets/javascripts/discourse/models/category.js
index d01e93110..2a731e30c 100644
--- a/app/assets/javascripts/discourse/models/category.js
+++ b/app/assets/javascripts/discourse/models/category.js
@@ -224,7 +224,7 @@ Discourse.Category.reopenClass({
 
   findSingleBySlug: function(slug) {
     return Discourse.Category.list().find(function(c) {
-      return Discourse.Category.slugFor(c) === slug;
+      return Discourse.Category.slugFor(c) === slug || Discourse.Category.slugFor(c) === encodeURI(slug);
     });
   },
 
@@ -254,7 +254,9 @@ Discourse.Category.reopenClass({
         if (slug === 'none') { return parentCategory; }
 
         category = categories.find(function(item) {
-          return item && item.get('parentCategory') === parentCategory && Discourse.Category.slugFor(item) === (parentSlug + "/" + slug);
+          return item && item.get('parentCategory') === parentCategory &&
+            (Discourse.Category.slugFor(item) === (parentSlug + "/" + slug) ||
+            Discourse.Category.slugFor(item) === encodeURIComponent(parentSlug) + "/" + encodeURIComponent(slug));
         });
       }
     } else {
diff --git a/app/controllers/topics_controller.rb b/app/controllers/topics_controller.rb
index 523813c10..358fdc5c5 100644
--- a/app/controllers/topics_controller.rb
+++ b/app/controllers/topics_controller.rb
@@ -427,7 +427,8 @@ class TopicsController < ApplicationController
   end
 
   def slugs_do_not_match
-    params[:slug] && @topic_view.topic.slug != params[:slug]
+    params[:slug] && (@topic_view.topic.slug != params[:slug] &&
+                      @topic_view.topic.slug != Rack::Utils.escape_path(params[:slug])) # maybe percent encoded
   end
 
   def redirect_to_correct_topic(topic, post_number=nil)
diff --git a/app/models/category.rb b/app/models/category.rb
index bfaf2f001..ea895cb02 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -207,14 +207,18 @@ SQL
 
     if slug.present?
       # santized custom slug
-      self.slug = Slug.for(slug)
+      self.slug = Slug.for(Rack::Utils.unescape(slug), '')
       errors.add(:slug, 'is already in use') if duplicate_slug?
     else
       # auto slug
-      self.slug = Slug.for(name)
-      return if self.slug.blank?
+      self.slug = Slug.for(name, '')
       self.slug = '' if duplicate_slug?
     end
+    # only allow to use category itself id. new_record doesn't have a id.
+    unless new_record?
+      match_id = /(\d+)-category/.match(self.slug)
+      errors.add(:slug, :invalid) if match_id && match_id[1] && match_id[1] != self.id.to_s
+    end
   end
 
   def slug_for_url
@@ -338,11 +342,13 @@ SQL
 
   def self.query_parent_category(parent_slug)
     self.where(slug: parent_slug, parent_category_id: nil).pluck(:id).first ||
+    self.where(slug: Rack::Utils.escape_path(parent_slug), parent_category_id: nil).pluck(:id).first ||
     self.where(id: parent_slug.to_i).pluck(:id).first
   end
 
   def self.query_category(slug_or_id, parent_category_id)
     self.where(slug: slug_or_id, parent_category_id: parent_category_id).includes(:featured_users).first ||
+    self.where(slug: Rack::Utils.escape_path(slug_or_id), parent_category_id: parent_category_id).includes(:featured_users).first ||
     self.where(id: slug_or_id.to_i, parent_category_id: parent_category_id).includes(:featured_users).first
   end
 
diff --git a/app/models/slug_setting.rb b/app/models/slug_setting.rb
new file mode 100644
index 000000000..b2be27fcb
--- /dev/null
+++ b/app/models/slug_setting.rb
@@ -0,0 +1,17 @@
+require_dependency 'enum_site_setting'
+
+class SlugSetting < EnumSiteSetting
+
+  VALUES = %w(ascii encoded none)
+
+  def self.valid_value?(val)
+    VALUES.include?(val)
+  end
+
+  def self.values
+    VALUES.map do |l|
+      {name: l, value: l}
+    end
+  end
+
+end
diff --git a/app/models/topic.rb b/app/models/topic.rb
index 8dc8df8bb..ef8d90d65 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -665,7 +665,7 @@ class Topic < ActiveRecord::Base
   def slug
     unless slug = read_attribute(:slug)
       return '' unless title.present?
-      slug = Slug.for(title).presence || "topic"
+      slug = Slug.for(title, 'topic')
       if new_record?
         write_attribute(:slug, slug)
       else
@@ -677,7 +677,7 @@ class Topic < ActiveRecord::Base
   end
 
   def title=(t)
-    slug = (Slug.for(t.to_s).presence || "topic")
+    slug = Slug.for(t.to_s, 'topic')
     write_attribute(:slug, slug)
     write_attribute(:title,t)
   end
diff --git a/app/serializers/notification_serializer.rb b/app/serializers/notification_serializer.rb
index 50d0b1ef7..86ede10b9 100644
--- a/app/serializers/notification_serializer.rb
+++ b/app/serializers/notification_serializer.rb
@@ -10,7 +10,7 @@ class NotificationSerializer < ApplicationSerializer
              :is_warning
 
   def slug
-    Slug.for(object.topic.title) if object.topic.present?
+    Slug.for(object.topic.title, 'topic') if object.topic.present?
   end
 
   def is_warning
diff --git a/app/serializers/user_action_serializer.rb b/app/serializers/user_action_serializer.rb
index 503aabe62..9fa5d292d 100644
--- a/app/serializers/user_action_serializer.rb
+++ b/app/serializers/user_action_serializer.rb
@@ -58,7 +58,7 @@ class UserActionSerializer < ApplicationSerializer
   end
 
   def slug
-    Slug.for(object.title)
+    Slug.for(object.title, 'topic')
   end
 
   def include_slug?
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 0db4cbc5a..8fba30e70 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1142,6 +1142,8 @@ en:
 
     prevent_anons_from_downloading_files: "Prevent anonymous users from downloading attachments. WARNING: this will prevent any non-image site assets posted as attachments from working."
 
+    slug_generation_method: "Choose a slug generation method. 'encoded' will generate percent encoding string. 'none' will disable slug at all."
+
     enable_emoji: "Enable emoji"
     emoji_set: "How would you like your emoji?"
     enforce_square_emoji: "Force a square aspect ratio to all emojis."
diff --git a/config/site_settings.yml b/config/site_settings.yml
index c43ea7480..30270d020 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -779,6 +779,10 @@ uncategorized:
     client: true
     default: true
 
+  slug_generation_method:
+    default: 'ascii'
+    enum: 'SlugSetting'
+
   # Search
   min_search_term_length:
     client: true
diff --git a/db/migrate/20140120155706_add_lounge_category.rb b/db/migrate/20140120155706_add_lounge_category.rb
index 95ac270a6..e67ae7de7 100644
--- a/db/migrate/20140120155706_add_lounge_category.rb
+++ b/db/migrate/20140120155706_add_lounge_category.rb
@@ -14,10 +14,11 @@ class AddLoungeCategory < ActiveRecord::Migration
 
         result = execute "INSERT INTO categories
                         (name, color, text_color, created_at, updated_at, user_id, slug, description, read_restricted, position)
-                 VALUES ('#{name}', 'EEEEEE', '652D90', now(), now(), -1, '#{Slug.for(name)}', '#{description}', true, 3)
+                 VALUES ('#{name}', 'EEEEEE', '652D90', now(), now(), -1, '', '#{description}', true, 3)
                  RETURNING id"
         category_id = result[0]["id"].to_i
 
+        execute "UPDATE categories SET slug='#{Slug.for(name, "#{category_id}-category")}' WHERE id=#{category_id}"
         execute "INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
                  VALUES ('lounge_category_id', 3, #{category_id}, now(), now())"
       end
diff --git a/db/migrate/20140122043508_add_meta_category.rb b/db/migrate/20140122043508_add_meta_category.rb
index fe50ec0bc..aa128bd7d 100644
--- a/db/migrate/20140122043508_add_meta_category.rb
+++ b/db/migrate/20140122043508_add_meta_category.rb
@@ -10,10 +10,11 @@ class AddMetaCategory < ActiveRecord::Migration
           result = Category.exec_sql "INSERT INTO categories
                           (name, color, text_color, created_at, updated_at, user_id, slug, description, read_restricted, position)
                    VALUES (:name, '808281', 'FFFFFF', now(), now(), -1, :slug, :description, true, 1)
-                   RETURNING id", name: name, slug: Slug.for(name), description: description
+                   RETURNING id", name: name, slug: '', description: description
 
           category_id = result[0]["id"].to_i
 
+          execute "UPDATE categories SET slug='#{Slug.for(name, "#{category_id}-category")}' WHERE id=#{category_id}"
           execute "INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
                    VALUES ('meta_category_id', 3, #{category_id}, now(), now())"
         end
diff --git a/db/migrate/20140227201005_add_staff_category.rb b/db/migrate/20140227201005_add_staff_category.rb
index 441dbaef3..6771fd978 100644
--- a/db/migrate/20140227201005_add_staff_category.rb
+++ b/db/migrate/20140227201005_add_staff_category.rb
@@ -8,10 +8,11 @@ class AddStaffCategory < ActiveRecord::Migration
         if Category.exec_sql("SELECT 1 FROM categories where name ilike '#{name}'").count == 0
           result = execute "INSERT INTO categories
                           (name, color, text_color, created_at, updated_at, user_id, slug, description, read_restricted, position)
-                   VALUES ('#{name}', '283890', 'FFFFFF', now(), now(), -1, '#{Slug.for(name)}', '#{description}', true, 2)
+                   VALUES ('#{name}', '283890', 'FFFFFF', now(), now(), -1, '', '#{description}', true, 2)
                    RETURNING id"
           category_id = result[0]["id"].to_i
 
+          execute "UPDATE categories SET slug='#{Slug.for(name, "#{category_id}-category")}' WHERE id=#{category_id}"
           execute "INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
                    VALUES ('staff_category_id', 3, #{category_id}, now(), now())"
         end
diff --git a/lib/onebox/engine/discourse_local_onebox.rb b/lib/onebox/engine/discourse_local_onebox.rb
index db4075b43..91d39e2f6 100644
--- a/lib/onebox/engine/discourse_local_onebox.rb
+++ b/lib/onebox/engine/discourse_local_onebox.rb
@@ -48,7 +48,7 @@ module Onebox
             return linked unless Guardian.new.can_see?(post)
 
             topic = post.topic
-            slug = Slug.for(topic.title)
+            slug = Slug.for(topic.title, 'topic')
 
             excerpt = post.excerpt(SiteSetting.post_onebox_maxlength)
             excerpt.gsub!("\n"," ")
diff --git a/lib/slug.rb b/lib/slug.rb
index 615207723..afde72162 100644
--- a/lib/slug.rb
+++ b/lib/slug.rb
@@ -1,21 +1,34 @@
 # encoding: utf-8
 
-
 module Slug
 
-  def self.for(string)
-    # TODO review if ja should use this
-    # ko asked for it to be removed
-    if ['zh_CN', 'ja'].include?(SiteSetting.default_locale)
-      unless defined? Stringex
-        require 'stringex_lite'
-      end
-      slug = string.to_url
-    else
-      slug = string.gsub("'", "").parameterize
-      slug.gsub!("_", "-")
-    end
-    slug =~ /[^\d]/ ? slug : '' # Reject slugs that only contain numbers, because they would be indistinguishable from id's.
+  def self.for(string, default = 'topic')
+    slug = case SiteSetting.slug_generation_method.to_sym
+           when :ascii then self.ascii_generator(string)
+           when :encoded then self.encoded_generator(string)
+           when :none then self.none_generator(string)
+           else raise Discourse::SiteSettingMissing
+           end
+    # Reject slugs that only contain numbers, because they would be indistinguishable from id's.
+    slug = (slug =~ /[^\d]/ ? slug : '')
+    slug.blank? ? default : slug
   end
 
+  private
+
+  def self.ascii_generator(string)
+    slug = string.gsub("'", "").parameterize
+    slug.gsub("_", "-")
+  end
+
+  def self.encoded_generator(string)
+    # strip and sanitized RFC 3986 reserved character and blank
+    string = string.strip.gsub(/\s+/, '-').gsub(/[:\/\?#\[\]@!\$\s&'\(\)\*\+,;=]+/, '')
+    string = Rack::Utils.escape_path(string)
+    string =~ /^-+$/ ? '' : string
+  end
+
+  def self.none_generator(string)
+    ''
+  end
 end
diff --git a/lib/tasks/build_test_topic.rake b/lib/tasks/build_test_topic.rake
index e135cabc9..40d801d7c 100644
--- a/lib/tasks/build_test_topic.rake
+++ b/lib/tasks/build_test_topic.rake
@@ -25,7 +25,7 @@ task 'build_test_topic' => :environment do
   first_post = PostCreator.new(evil_trout, raw: "This is the original post.", title: "pushState/replaceState test topic").create
   topic = first_post.topic
 
-  topic_url = "#{Discourse.base_url}/t/#{Slug.for(topic.title)}/#{topic.id}"
+  topic_url = "#{Discourse.base_url}/t/#{Slug.for(topic.title, 'topic')}/#{topic.id}"
 
   99.times do |i|
     post_number = (i + 2)
diff --git a/spec/components/slug_spec.rb b/spec/components/slug_spec.rb
index 166f6b3cb..827adf823 100644
--- a/spec/components/slug_spec.rb
+++ b/spec/components/slug_spec.rb
@@ -5,60 +5,141 @@ require 'slug'
 
 describe Slug do
 
-  it 'replaces spaces with hyphens' do
-    expect(Slug.for("hello world")).to eq('hello-world')
+  describe '#for' do
+    context 'ascii generator' do
+      before { SiteSetting.slug_generation_method = 'ascii' }
+
+      it 'generates the slug' do
+        expect(Slug.for("hello world", 'topic')).to eq('hello-world')
+      end
+
+      it 'generates default slug when nothing' do
+        expect(Slug.for('', 'topic')).to eq('topic')
+      end
+
+      it "doesn't generate slugs that are just numbers" do
+        expect(Slug.for('123', 'topic')).to eq('topic')
+      end
+    end
+
+    context 'encoded generator' do
+      before { SiteSetting.slug_generation_method = 'encoded' }
+      after { SiteSetting.slug_generation_method = 'ascii' }
+
+      it 'generates the slug' do
+        expect(Slug.for("熱帶風暴畫眉", 'topic')).to eq('%E7%86%B1%E5%B8%B6%E9%A2%A8%E6%9A%B4%E7%95%AB%E7%9C%89')
+      end
+
+      it 'generates default slug when nothing' do
+        expect(Slug.for('', 'topic')).to eq('topic')
+      end
+
+      it "doesn't generate slugs that are just numbers" do
+        expect(Slug.for('123', 'topic')).to eq('topic')
+      end
+    end
+
+    context 'none generator' do
+      before { SiteSetting.slug_generation_method = 'none' }
+      after { SiteSetting.slug_generation_method = 'ascii' }
+
+      it 'generates the slug' do
+        expect(Slug.for("hello world", 'category')).to eq('category')
+        expect(Slug.for("hello world", 'topic')).to eq('topic')
+        expect(Slug.for('', 'topic')).to eq('topic')
+        expect(Slug.for('123', 'topic')).to eq('topic')
+      end
+    end
   end
 
-  it 'changes accented characters' do
-    expect(Slug.for('àllo')).to eq('allo')
+  describe '#ascii_generator' do
+    before { SiteSetting.slug_generation_method = 'ascii' }
+
+    it 'replaces spaces with hyphens' do
+      expect(Slug.ascii_generator("hello world")).to eq('hello-world')
+    end
+
+    it 'changes accented characters' do
+      expect(Slug.ascii_generator('àllo')).to eq('allo')
+    end
+
+    it 'replaces symbols' do
+      expect(Slug.ascii_generator('evil#trout')).to eq('evil-trout')
+    end
+
+    it 'handles a.b.c properly' do
+      expect(Slug.ascii_generator("a.b.c")).to eq("a-b-c")
+    end
+
+    it 'handles double dots right' do
+      expect(Slug.ascii_generator("a....b.....c")).to eq("a-b-c")
+    end
+
+    it 'strips trailing punctuation' do
+      expect(Slug.ascii_generator("hello...")).to eq("hello")
+    end
+
+    it 'strips leading punctuation' do
+      expect(Slug.ascii_generator("...hello")).to eq("hello")
+    end
+
+    it 'handles our initial transliteration' do
+      from = "àáäâčďèéëěêìíïîľĺňòóöôŕřšťůùúüûýžñç"
+      to   = "aaaacdeeeeeiiiillnoooorrstuuuuuyznc"
+      expect(Slug.ascii_generator(from)).to eq(to)
+    end
+
+    it 'replaces underscores' do
+      expect(Slug.ascii_generator("o_o_o")).to eq("o-o-o")
+    end
+
+    it "doesn't keep single quotes within word" do
+      expect(Slug.ascii_generator("Jeff hate's this")).to eq("jeff-hates-this")
+    end
+
+    it 'generates null when nothing' do
+      expect(Slug.ascii_generator('')).to eq('')
+    end
+
+    it "keeps number unchanged" do
+      expect(Slug.ascii_generator('123')).to eq('123')
+    end
   end
 
-  it 'replaces symbols' do
-    expect(Slug.for('evil#trout')).to eq('evil-trout')
+  describe '#encoded_generator' do
+    before { SiteSetting.slug_generation_method = 'encoded' }
+    after { SiteSetting.slug_generation_method = 'ascii' }
+
+    it 'generates precentage encoded string' do
+      expect(Slug.encoded_generator("Jeff hate's !~-_|,=#this")).to eq("Jeff-hates-%7E-_%7Cthis")
+      expect(Slug.encoded_generator("뉴스피드")).to eq("%EB%89%B4%EC%8A%A4%ED%94%BC%EB%93%9C")
+      expect(Slug.encoded_generator("آموزش اضافه کردن لینک اختیاری به هدر")).to eq("%D8%A2%D9%85%D9%88%D8%B2%D8%B4-%D8%A7%D8%B6%D8%A7%D9%81%D9%87-%DA%A9%D8%B1%D8%AF%D9%86-%D9%84%DB%8C%D9%86%DA%A9-%D8%A7%D8%AE%D8%AA%DB%8C%D8%A7%D8%B1%DB%8C-%D8%A8%D9%87-%D9%87%D8%AF%D8%B1")
+      expect(Slug.encoded_generator("熱帶風暴畫眉")).to eq("%E7%86%B1%E5%B8%B6%E9%A2%A8%E6%9A%B4%E7%95%AB%E7%9C%89")
+    end
+
+    it 'reject RFC 3986 reserved character and blank' do
+      expect(Slug.encoded_generator(":/?#[]@!$ &'()*+,;=")).to eq("")
+    end
+
+    it 'generates null when nothing' do
+      expect(Slug.encoded_generator('')).to eq('')
+    end
+
+    it "keeps number unchanged" do
+      expect(Slug.encoded_generator('123')).to eq('123')
+    end
   end
 
-  it 'handles a.b.c properly' do
-    expect(Slug.for("a.b.c")).to eq("a-b-c")
-  end
+  describe '#none_generator' do
+    before { SiteSetting.slug_generation_method = 'none' }
+    after { SiteSetting.slug_generation_method = 'ascii' }
 
-  it 'handles double dots right' do
-    expect(Slug.for("a....b.....c")).to eq("a-b-c")
+    it 'generates nothing' do
+      expect(Slug.none_generator("Jeff hate's this")).to eq('')
+      expect(Slug.none_generator(nil)).to eq('')
+      expect(Slug.none_generator('')).to eq('')
+      expect(Slug.none_generator('31')).to eq('')
+    end
   end
-
-  it 'strips trailing punctuation' do
-    expect(Slug.for("hello...")).to eq("hello")
-  end
-
-  it 'strips leading punctuation' do
-    expect(Slug.for("...hello")).to eq("hello")
-  end
-
-  it 'handles our initial transliteration' do
-    from = "àáäâčďèéëěêìíïîľĺňòóöôŕřšťůùúüûýžñç"
-    to   = "aaaacdeeeeeiiiillnoooorrstuuuuuyznc"
-    expect(Slug.for(from)).to eq(to)
-  end
-
-  it 'replaces underscores' do
-    expect(Slug.for("o_o_o")).to eq("o-o-o")
-  end
-
-  it "doesn't generate slugs that are just numbers" do
-    expect(Slug.for('123')).to be_blank
-  end
-
-  it "doesn't generate slugs that are just numbers" do
-    expect(Slug.for('2')).to be_blank
-  end
-
-  it "doesn't keep single quotes within word" do
-    expect(Slug.for("Jeff hate's this")).to eq("jeff-hates-this")
-  end
-
-  it "translate the chineses" do
-    SiteSetting.default_locale = 'zh_CN'
-    expect(Slug.for("习近平:中企承建港口电站等助斯里兰卡发展")).to eq("xi-jin-ping-zhong-qi-cheng-jian-gang-kou-dian-zhan-deng-zhu-si-li-lan-qia-fa-zhan")
-  end
-
 end
 
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index f8d5f39c7..33a56e201 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -169,22 +169,54 @@ describe Category do
   end
 
   describe 'non-english characters' do
-    let(:category) { Fabricate(:category, name: "测试") }
+    context 'uses ascii slug generator' do
+      before do
+        SiteSetting.slug_generation_method = 'ascii'
+        @category = Fabricate(:category, name: "测试")
+      end
+      after { @category.destroy }
 
-    it "creates a blank slug, this is OK." do
-      expect(category.slug).to be_blank
-      expect(category.slug_for_url).to eq("#{category.id}-category")
+      it "creates a blank slug" do
+        expect(@category.slug).to be_blank
+        expect(@category.slug_for_url).to eq("#{@category.id}-category")
+      end
     end
 
-    it "creates a localized slug if default locale is zh_CN" do
-      SiteSetting.default_locale = 'zh_CN'
-      expect(category.slug).to_not be_blank
-      expect(category.slug_for_url).to eq("ce-shi")
+    context 'uses none slug generator' do
+      before do
+        SiteSetting.slug_generation_method = 'none'
+        @category = Fabricate(:category, name: "测试")
+      end
+      after do
+        SiteSetting.slug_generation_method = 'ascii'
+        @category.destroy
+      end
+
+      it "creates a blank slug" do
+        expect(@category.slug).to be_blank
+        expect(@category.slug_for_url).to eq("#{@category.id}-category")
+      end
+    end
+
+    context 'uses encoded slug generator' do
+      before do
+        SiteSetting.slug_generation_method = 'encoded'
+        @category = Fabricate(:category, name: "测试")
+      end
+      after do
+        SiteSetting.slug_generation_method = 'ascii'
+        @category.destroy
+      end
+
+      it "creates a slug" do
+        expect(@category.slug).to eq("%E6%B5%8B%E8%AF%95")
+        expect(@category.slug_for_url).to eq("%E6%B5%8B%E8%AF%95")
+      end
     end
   end
 
   describe 'slug would be a number' do
-    let(:category) { Fabricate(:category, name: "2") }
+    let(:category) { Fabricate.build(:category, name: "2") }
 
     it 'creates a blank slug' do
       expect(category.slug).to be_blank
@@ -193,21 +225,25 @@ describe Category do
   end
 
   describe 'custom slug can be provided' do
-    it 'has the custom value' do
-      c = Fabricate(:category, name: "Cats", slug: "cats-category")
-      expect(c.slug).to eq("cats-category")
-    end
+    it 'can be sanitized' do
+      @c = Fabricate(:category, name: "Fun Cats", slug: "fun-cats")
+      @cat = Fabricate(:category, name: "love cats", slug: "love-cats")
 
-    it 'and be sanitized' do
-      c = Fabricate(:category, name: 'Cats', slug: '  invalid slug')
-      expect(c.slug).to eq('invalid-slug')
-    end
+      @c.slug = '  invalid slug'
+      @c.save
+      expect(@c.slug).to eq('invalid-slug')
 
-    it 'fails if custom slug is duplicate with existing' do
-      c1 = Fabricate(:category, name: "Cats", slug: "cats")
-      c2 = Fabricate.build(:category, name: "More Cats", slug: "cats")
-      expect(c2).to_not be_valid
-      expect(c2.errors[:slug]).to be_present
+      c = Fabricate.build(:category, name: "More Fun Cats", slug: "love-cats")
+      expect(c).not_to be_valid
+      expect(c.errors[:slug]).to be_present
+
+      @cat.slug = "#{@c.id}-category"
+      expect(@cat).not_to be_valid
+      expect(@cat.errors[:slug]).to be_present
+
+      @cat.slug = "#{@cat.id}-category"
+      expect(@cat).to be_valid
+      expect(@cat.errors[:slug]).not_to be_present
     end
   end
 
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index 66ce8e17b..105894c57 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -12,28 +12,64 @@ describe Topic do
   it { is_expected.to rate_limit }
 
   context 'slug' do
-
     let(:title) { "hello world topic" }
-    let(:slug) { "hello-world-slug" }
+    let(:slug) { "hello-world-topic" }
+    context 'encoded generator' do
+      before { SiteSetting.slug_generation_method = 'encoded' }
+      after { SiteSetting.slug_generation_method = 'ascii' }
 
-    it "returns a Slug for a title" do
-      Slug.expects(:for).with(title).returns(slug)
-      expect(Fabricate.build(:topic, title: title).slug).to eq(slug)
+      it "returns a Slug for a title" do
+        Slug.expects(:for).with(title, 'topic').returns(slug)
+        expect(Fabricate.build(:topic, title: title).slug).to eq(slug)
+      end
+
+      context 'for cjk characters' do
+        let(:title) { "熱帶風暴畫眉" }
+        let(:slug) { "%E7%86%B1%E5%B8%B6%E9%A2%A8%E6%9A%B4%E7%95%AB%E7%9C%89" }
+        it "returns encoded Slug for a title" do
+          Slug.expects(:for).with(title, 'topic').returns(slug)
+          expect(Fabricate.build(:topic, title: title).slug).to eq(slug)
+        end
+      end
+
+      context 'for numbers' do
+        let(:title) { "123456789" }
+        let(:slug) { "topic" }
+        it 'generates default slug' do
+          Slug.expects(:for).with(title, 'topic').returns("topic")
+          expect(Fabricate.build(:topic, title: title).slug).to eq("topic")
+        end
+      end
     end
 
-    let(:chinese_title) { "习近平:中企承建港口电站等助斯里兰卡发展" }
-    let(:chinese_slug) { "xi-jin-ping-zhong-qi-cheng-jian-gang-kou-dian-zhan-deng-zhu-si-li-lan-qia-fa-zhan" }
+    context 'none generator' do
+      before { SiteSetting.slug_generation_method = 'none' }
+      after { SiteSetting.slug_generation_method = 'ascii' }
+      let(:title) { "熱帶風暴畫眉" }
+      let(:slug) { "topic" }
 
-    it "returns a symbolized slug for a chinese title" do
-      SiteSetting.default_locale = 'zh_CN'
-      expect(Fabricate.build(:topic, title: chinese_title).slug).to eq(chinese_slug)
+      it "returns a Slug for a title" do
+        Slug.expects(:for).with(title, 'topic').returns('topic')
+        expect(Fabricate.build(:topic, title: title).slug).to eq(slug)
+      end
     end
 
-    it "returns 'topic' when the slug is empty (say, non-english chars)" do
-      Slug.expects(:for).with(title).returns("")
-      expect(Fabricate.build(:topic, title: title).slug).to eq("topic")
-    end
+    context '#ascii_generator' do
+      before { SiteSetting.slug_generation_method = 'ascii' }
+      it "returns a Slug for a title" do
+        Slug.expects(:for).with(title, 'topic').returns(slug)
+        expect(Fabricate.build(:topic, title: title).slug).to eq(slug)
+      end
 
+      context 'for cjk characters' do
+        let(:title) { "熱帶風暴畫眉" }
+        let(:slug) { 'topic' }
+        it "returns 'topic' when the slug is empty (say, non-latin characters)" do
+          Slug.expects(:for).with(title, 'topic').returns("topic")
+          expect(Fabricate.build(:topic, title: title).slug).to eq("topic")
+        end
+      end
+    end
   end
 
   context "updating a title to be shorter" do
diff --git a/test/javascripts/models/category-test.js.es6 b/test/javascripts/models/category-test.js.es6
index 5334b67dd..b005ec116 100644
--- a/test/javascripts/models/category-test.js.es6
+++ b/test/javascripts/models/category-test.js.es6
@@ -9,6 +9,7 @@ test('slugFor', function(){
   slugFor(Discourse.Category.create({slug: 'hello'}), "hello", "It calculates the proper slug for hello");
   slugFor(Discourse.Category.create({id: 123, slug: ''}), "123-category", "It returns id-category for empty strings");
   slugFor(Discourse.Category.create({id: 456}), "456-category", "It returns id-category for undefined slugs");
+  slugFor(Discourse.Category.create({slug: '熱帶風暴畫眉'}), "熱帶風暴畫眉", "It can be non english characters");
 
   var parentCategory = Discourse.Category.create({id: 345, slug: 'darth'});
   slugFor(Discourse.Category.create({slug: 'luke', parentCategory: parentCategory}),
@@ -27,16 +28,45 @@ test('slugFor', function(){
 
 
 test('findBySlug', function() {
+  expect(6);
+
   var darth = Discourse.Category.create({id: 1, slug: 'darth'}),
-      luke = Discourse.Category.create({id: 2, slug: 'luke', parentCategory: darth}),
-      categoryList = [darth, luke];
+    luke = Discourse.Category.create({id: 2, slug: 'luke', parentCategory: darth}),
+    hurricane = Discourse.Category.create({id: 3, slug: '熱帶風暴畫眉'}),
+    newsFeed = Discourse.Category.create({id: 4, slug: '뉴스피드', parentCategory: hurricane}),
+    time = Discourse.Category.create({id: 5, slug: '时间', parentCategory: darth}),
+    bah = Discourse.Category.create({id: 6, slug: 'bah', parentCategory: hurricane}),
+    categoryList = [darth, luke, hurricane, newsFeed, time, bah];
 
   sandbox.stub(Discourse.Category, 'list').returns(categoryList);
 
-  equal(Discourse.Category.findBySlug('darth'), darth, 'we can find a parent category');
-  equal(Discourse.Category.findBySlug('luke', 'darth'), luke, 'we can find a child with parent');
-  blank(Discourse.Category.findBySlug('luke'), 'luke is blank without the parent');
-  blank(Discourse.Category.findBySlug('luke', 'leia'), 'luke is blank with an incorrect parent');
+  deepEqual(Discourse.Category.findBySlug('darth'), darth, 'we can find a category');
+  deepEqual(Discourse.Category.findBySlug('luke', 'darth'), luke, 'we can find the other category with parent category');
+  deepEqual(Discourse.Category.findBySlug('熱帶風暴畫眉'), hurricane, 'we can find a category with CJK slug');
+  deepEqual(Discourse.Category.findBySlug('뉴스피드', '熱帶風暴畫眉'), newsFeed, 'we can find a category with CJK slug whose parent slug is also CJK');
+  deepEqual(Discourse.Category.findBySlug('时间', 'darth'), time, 'we can find a category with CJK slug whose parent slug is english');
+  deepEqual(Discourse.Category.findBySlug('bah', '熱帶風暴畫眉'), bah, 'we can find a category with english slug whose parent slug is CJK');
+});
+
+test('findSingleBySlug', function() {
+  expect(6);
+
+  var darth = Discourse.Category.create({id: 1, slug: 'darth'}),
+    luke = Discourse.Category.create({id: 2, slug: 'luke', parentCategory: darth}),
+    hurricane = Discourse.Category.create({id: 3, slug: '熱帶風暴畫眉'}),
+    newsFeed = Discourse.Category.create({id: 4, slug: '뉴스피드', parentCategory: hurricane}),
+    time = Discourse.Category.create({id: 5, slug: '时间', parentCategory: darth}),
+    bah = Discourse.Category.create({id: 6, slug: 'bah', parentCategory: hurricane}),
+    categoryList = [darth, luke, hurricane, newsFeed, time, bah];
+
+  sandbox.stub(Discourse.Category, 'list').returns(categoryList);
+
+  deepEqual(Discourse.Category.findSingleBySlug('darth'), darth, 'we can find a category');
+  deepEqual(Discourse.Category.findSingleBySlug('darth/luke'), luke, 'we can find the other category with parent category');
+  deepEqual(Discourse.Category.findSingleBySlug('熱帶風暴畫眉'), hurricane, 'we can find a category with CJK slug');
+  deepEqual(Discourse.Category.findSingleBySlug('熱帶風暴畫眉/뉴스피드'), newsFeed, 'we can find a category with CJK slug whose parent slug is also CJK');
+  deepEqual(Discourse.Category.findSingleBySlug('darth/时间'), time, 'we can find a category with CJK slug whose parent slug is english');
+  deepEqual(Discourse.Category.findSingleBySlug('熱帶風暴畫眉/bah'), bah, 'we can find a category with english slug whose parent slug is CJK');
 });
 
 test('findByIds', function() {