Men use thumbs, women use index fingers?

This is totally unscientific as I had a sample group of 5 people...

Of the 2 guys and 3 girls I had testing my app, I found that they all held the device very differently. The two right-handed guys I gave it to all held the phone in their right hand and used their thumb to to move the pieces on the board. The girls held the device in their left hand and used their index finger to move the pieces.

I use the index finger to play - mainly because my hand is too small to hold and operate the device... it's the same reason I'm not awesome at playing the guitar!

When building my game I had to test that my buttons and hyperlinks were wide enough to work with both the thumb and index finger, as well as making sure the tile I was dragging was visible when dragged with either finger.

For the tile during drag, I subtracted the tile height and a little bit of buffer so that the tile would remain above the finger during a drag. This was a process of trial and error until it felt "right".

The best way to see what I mean is to give it a go!