iPad Chessboard for Analysis

Yes, I've seen this question asked before. No, I haven't seen it answered.

All I (and others) want is the ability to set up pieces, play moves, and easily revert to previous positions, so you can follow a variant and come back to the starting point.

I cannot believe this functionality isn't currently available! The closest is Tiger Chess. When you take back a move, it creates a variant. You can follow the variant, then click a button and go back to the original position. Variants can be nested.

The problem for me is that 1) the menu action could be a bit more accessible, but more importantly, 2) the app now only runs in landscape mode, which means I can't hold it in my lap beside a book. Hopefully, they'll add portrait mode soon.

Note: I don't care about whether the app can load PGN files. I don't care what its analysis strength is. I just want to use it as a "smart" chessboard in order to study a chess book.

This sounds so simple that I might even write it myself.

Have you tried the Shredder app for Ipad?  I just got it a few days ago for $1.99  It allows you to set up positions...clear the board and put pieces wherever and then make the moves.  I know at any point you can then play the position out against Shredder. After you set up a position, you can use the arrow keys to take back moves you make.  Plus, they have a neat little "endgame database" cloud system, if you are on wi-fi, and you have an endgame that has 6-men or less, you just touch a button, and it will access instantly the tablebases for endgames and tell you which moves draw and which moves lose or win and how many moves for each.    

For 2 bucks, it is worth a try.

Is there a reason that this site doesn't have such a function? I have wanted something like this for a while but there it doesn't exist on this site.

With all due respect, TL, your response is characteristic of many of those I've seen on this topic.

1) All decent chess programs let you set up a position.

2) All decent programs let you take back moves one by one.

3) #1 and #2 are not what I'm asking for. I want it to understand what a variation is (like Chess Tiger).

4) The program's own analysis capabilities are irrelevant unless it supports my (and everyone else's) workflow with a chess book: set up a position, then work through moves and nested variations.

Since this can't be that difficult, there must be some reason I'm missing that it doesn't exist.

It looks like Chess Partner comes close to what I want. It supports variations, but I would like it even better if it let you pop up to the beginning of a variation with one gesture.

So I'm writing my own. Or rather, I'm adapting Stockfish for iOS to provide nothing but a iPad chess board to use with chess books.

One feature I want is the ability to simply rearrange the pieces on the board (hey, just like a real chess board). So instead of having an "Edit Position" function that brings up a separate window, I'm just going to let the user rearrange the pieces!

It's called Stosh (cut-down Stockfish). The source code is at https://github.com/mwilden/stosh.