diff --git a/.gitmodules b/.gitmodules
index 432a1ff..dadb758 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "gun"]
 	path = gun
 	url = https://github.com/amark/gun
+[submodule "node-deep-equal"]
+	path = node-deep-equal
+	url = gogs@jessemcdonald.info:nybble/node-deep-equal.git
diff --git a/index.html b/index.html
index 6237678..7b4340b 100644
--- a/index.html
+++ b/index.html
@@ -260,20 +260,21 @@
          </div>
       </div>
 
+      <script src="jquery-ui/external/jquery/jquery.js"></script>
+      <script src="jquery-ui/dist/jquery-ui.min.js"></script>
+      <script src="jquery-ui-touch-punch/jquery.ui.touch-punch.min.js"></script>
       <script>
          console.real_log = console.log;
          console.log = () => {};
          //console.STAT = console.real_log;
       </script>
-      <script src="jquery-ui/external/jquery/jquery.js"></script>
-      <script src="jquery-ui/dist/jquery-ui.min.js"></script>
-      <script src="jquery-ui-touch-punch/jquery.ui.touch-punch.min.js"></script>
       <script src="gun/gun.js"></script>
       <script src="gun/sea.js"></script>
       <script src="gun/lib/webrtc.js"></script>
       <script>
          console.log = console.real_log;
       </script>
+      <script src="node-deep-equal/index.js"></script>
       <script src="js/chess.js"></script>
       <script src="js/todo.js"></script>
    </body>
diff --git a/js/chess.js b/js/chess.js
index 42ca822..9bdf029 100644
--- a/js/chess.js
+++ b/js/chess.js
@@ -510,7 +510,14 @@ function renderBoard(board){
    $('#cb_history').text(renderHistory(board));
 }
 
-function setVisibleBoard(board, live){
+function setVisibleBoard(board){
+   const cb_board = $('#cb_board').first();
+
+   const currentBoard = cloneJSON(cb_board.data('board'));
+   delete currentBoard.subsequent;
+
+   const live = deepEqual(board, currentBoard);
+
    $('#cb_board').data('visible_board', board);
    renderBoard(board);
 
@@ -521,6 +528,7 @@ function setVisibleBoard(board, live){
    $('#cb_nav_next_turn').attr('disabled', board.subsequent ? false : true);
 
    if (live) {
+      /* the 'visible' board may be missing .subsequent */
       const liveBoard = $('#cb_board').data('board');
       $('#cb_undo').attr('disabled', liveBoard.prior ? false : true);
       $('#cb_redo').attr('disabled', liveBoard.subsequent ? false : true);
@@ -543,14 +551,12 @@ function setCurrentBoard(board){
    const cb_board = $('#cb_board').first();
    cb_board.data('board', board);
 
-   const boardState = JSON.stringify(board);
-
    /* navigation should not include the redo stack */
-   const visible = JSON.parse(boardState);
+   const visible = cloneJSON(board);
    delete visible.subsequent;
-   setVisibleBoard(visible, true);
+   setVisibleBoard(visible);
 
-   if ($('#cb_notify')[0].checked && boardState !== cb_board.data('last_state')) {
+   if ($('#cb_notify')[0].checked && !deepEqual(board, cb_board.data('last_state'))) {
       /* ignore partial moves and undo/redo */
       if (!board.phantom && !board.subsequent) {
          const gameString = cb_board.data('lightName') + ' vs. ' + cb_board.data('darkName');
@@ -558,7 +564,7 @@ function setCurrentBoard(board){
       }
    }
 
-   cb_board.data('last_state', boardState);
+   cb_board.data('last_state', cloneJSON(board));
 }
 
 function randomId(){
@@ -576,9 +582,8 @@ function putState(board){
    var boardElem = $('#cb_board');
    var gameId = boardElem.data('gameId');
    var game = gun.get(PacoSakoUUID).get('games').get(gameId);
-   var state = JSON.stringify(board);
-   boardElem.data('last_state', state);
-   game.put({ board: state });
+   boardElem.data('last_state', cloneJSON(board));
+   game.put({ board: JSON.stringify(board) });
    putMeta();
 }
 
@@ -628,7 +633,7 @@ function switchGameId(newId){
    /* this will be the starting state if no data is received from peers */
    var newBoard = initialBoard();
    setCurrentBoard(newBoard);
-   boardElem.data('last_state', JSON.stringify(newBoard));
+   boardElem.data('last_state', cloneJSON(newBoard));
 
    boardElem.data('lightName', 'Light');
    boardElem.data('darkName', 'Dark');
@@ -841,7 +846,7 @@ $(function (){
    $('#cb_nav_last').on('click', function(){
       const visible = cloneJSON($('#cb_board').data('board'));
       delete visible.subsequent;
-      setVisibleBoard(visible, true);
+      setVisibleBoard(visible);
    });
 
    $('#cb_reset').on('click', function(){
diff --git a/node-deep-equal b/node-deep-equal
new file mode 160000
index 0000000..007fae2
--- /dev/null
+++ b/node-deep-equal
@@ -0,0 +1 @@
+Subproject commit 007fae260428db9eb350e752e52fb806adb24c56