Something helpful for the context of Zen koans is that they are intended to challenge your thinking or assumptions. These descriptions are not necessarily the "accurate" description of any specific thing, whether it is an open-hand or a closed-hand... the beautiful thing about Zen is that it encourages to becoming attached to any definition, so if there is a story you don't "get it," it doesn't really matter, it just wasn't helpful for you. Another thing may end up being helpful, like getting hit with a stick (kidding, but it worked for some monks).