diff --git a/nikoli.rb b/nikoli.rb
index 8a35645..4e422db 100755
--- a/nikoli.rb
+++ b/nikoli.rb
@@ -7,7 +7,7 @@ require 'coffee-script'
 require 'slim'
 require 'sass'
 
-GAMES = %i{nurikabe sudoku}
+GAMES = %i{hitori nurikabe sudoku}
 
 get('/application.css') { scss :application }
 get('/application.js') { coffee :application }
diff --git a/views/application.scss b/views/application.scss
index d16f334..b875c90 100644
--- a/views/application.scss
+++ b/views/application.scss
@@ -69,6 +69,12 @@ ul {
   background-color: #aaa;
 }
 
+.hitori {
+  .black {
+    opacity: 0.1;
+  }
+}
+
 .sudoku {
   $sudoku-separation: 5px;
 
diff --git a/views/hitori.coffee b/views/hitori.coffee
new file mode 100644
index 0000000..645b099
--- /dev/null
+++ b/views/hitori.coffee
@@ -0,0 +1,93 @@
+window.Hitori = class Nurikabe
+  constructor: (@board) ->
+    @board.classList.add 'hitori'
+
+    @grid = document.createElement 'div'
+    @grid.classList.add 'game-container'
+    @board.appendChild @grid
+
+    buttons_div = document.createElement 'div'
+    buttons = {check: 'Check', reset: 'Reset', newgame: 'New game', help: '?'}
+
+    for k,v of buttons
+      button = document.createElement 'button'
+      button.innerHTML = v
+      button.classList.add k
+
+      buttons_div.appendChild button
+
+    @board.appendChild buttons_div
+
+    @board.querySelector('.check').addEventListener('click', @check.bind(this))
+    @board.querySelector('.reset').addEventListener('click', @reset.bind(this))
+
+  check: ->
+    errors = @errors()
+
+    if errors.length == 0
+      alert 'Congratulations!'
+    else
+      alert errors.map((el) -> el.message).join()
+
+  errors: ->
+    solution = @toArray()
+    errors = []
+    processed_cells = []
+    white_stream = new Nikoli.Stream(solution)
+
+    for i in [0...solution.length]
+      row = solution[i]
+      for j in [0...row.length]
+        cell = solution[i][j]
+
+        if cell >= 0
+          white_stream.calculate({x: i, y: j}) if white_stream.empty()
+
+          if !white_stream.include({x: i, y: j})
+            errors.push {row: i, column: j, message: 'The stream must be continuous'}
+          # TODO check for duplicates in rows and columns
+        else
+          adjacent_cells = [
+            {x: i+1, y: j},
+            {x: i-1, y: j},
+            {x: i, y: j+1},
+            {x: i, y: j-1}
+          ]
+          if adjacent_cells.some((el) ->
+            0 <= el.x < solution.length && 0 <= el.y < solution[el.x].length && solution[el.x][el.y] == -1)
+            errors.push {row: i, column: j, message: 'Adjacent filled-in cells'}
+
+    errors
+
+  generate: (game, solution = false) ->
+    @game = game if game?
+    @grid.innerHTML = @game.map((row) ->
+      '<div class="grid-row">' + row.map((cell) ->
+        "<div class=\"grid-cell\">#{cell}</div>"
+      ).join('') + '</div>'
+    ).join('')
+
+    for cell in board.querySelectorAll('.grid-cell')
+      cell.addEventListener 'click', ((evenment) => @toggle evenment.target), false
+
+    return
+
+  reset: ->
+    @generate()
+
+  toggle: (cell) ->
+    if cell.classList.contains 'black'
+      cell.classList.remove 'black'
+      cell.classList.add 'white'
+    else if cell.classList.contains 'white'
+      cell.classList.remove 'white'
+    else
+      cell.classList.add 'black'
+
+  toArray: ->
+    [].map.call @grid.querySelectorAll('.grid-row'), (row) ->
+      [].map.call row.querySelectorAll('.grid-cell'), (cell) ->
+        if cell.classList.contains('black')
+          -1
+        else
+          parseInt(cell.innerHTML)
diff --git a/views/hitori.slim b/views/hitori.slim
new file mode 100644
index 0000000..0c4f3af
--- /dev/null
+++ b/views/hitori.slim
@@ -0,0 +1,22 @@
+- content_for(:title) { 'Hitori' }
+
+h1 Hitori
+#board
+
+script type="text/javascript" src="/hitori.js"
+javascript:
+  document.addEventListener("DOMContentLoaded", function() {
+    var game = [
+      [4,5,6,8,3,7,8,1],
+      [1,1,1,4,8,6,7,2],
+      [5,4,7,6,3,1,2,8],
+      [7,4,5,3,2,8,1,6],
+      [2,2,2,7,1,4,4,4],
+      [8,7,4,5,5,2,6,3],
+      [6,7,8,5,5,4,3,2],
+      [3,3,3,2,4,6,1,7]
+    ];
+
+    hitori = new Hitori(document.getElementById('board'));
+    hitori.generate(game);
+  });