You need to remember the club goes down and out UNTIL it starts going up and in.
Looking down at the ground from above, the "apex of the swing-arc" is gonna be in your divot, if you are taking one. The "apex" is where your lowpoint is.
If you are not taking a divot (say the ball is teed up or sitting up in the grass) the "top of the rainbow" (again- from above view) could even be behind and outside the ball. In this case you will be hitting the ball as your club moves up and in.
With your shanks it's pretty common to have a too open clubface that needs adjusting.
I also get em sometimes if I swing too far from the inside or from the outside. (you may be able to feel/see how this could direct the hosel at the ball)
All else being equal I get them far more when I am using short clubs. (hitting down on it more)
Sometimes it helps to take it back more closed (i.e. Twistaway) or to full roll it in the downswing to GET it closed. Even if just for a drill. (hit balls) Of course there's also nothing wrong with doing either all the time if they work for you. I have hit some of my best shots doing both. (including my longest and best drive ever full rolling it)
I find nowadays I like to setup with the ball a little bit towards the toe. (Hogan used to, among others I am sure) I don't find myself "toe-shanking" it anymore (used to be a chronic user) so I can actually do this.
I like to think of it as a little bit of "anti-shank insurance." I open my clubface a lot more than I used to and will still often feel prone to shanks, especially if I am hitting down on it a fair bit. I think having the ball off the toe may help me.
Shanks can be a pretty fickle thing. It's no cure-all but even tension (from whatever source- perhaps anxiety) can probably contribute. (tense up-> lose fluidity-> leave the clubface open)
Another idea that I like is from the "Coleman Estate" Ben Hogan footage, if you have seen it. (near the end I think when they are zoomed on his grip) He talks about getting the right forefinger right behind the shaft at impact.
Hogan says something like: "It's no pressure down or around the shaft- just behind."
In some ways that may not seem to jive with a full roll which is interesting...
...esp. because of this image from Hogan's "5 Lessons" where he does describe a "full-roll":
To me though, if I roll it open in the backswing like I do most of the time (screwdriver-like "swivel"...as opposed to "Twistaway") I have a hard time getting it too closed past the ball, despite my efforts. As a sidenote I suspect that the forces that keep the clubhead trailing and the toe falling open (Brian has talked about this recently) come into play in that. This is all just theory.
Relating to the Hogan video again, one drill I can think of is to (gently!) palm slap or backhand (depends on what hand) a wall. If you ARE gonna roll it open you had better get it closed to get "flat on flat" contact with the wall. (like the Hogan image above, actually) Brian has also talked before about "hitting the box."
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Just my 3 cents...Brian or someone else with experience may be able to better advise you than me.
