Progress with calculation skills
Since a few days I'm working on "tactics that I always got wrong". With that option it is great to see my calculation improvement over the years (2012-2016).
Here's a not so easy puzzle that I got wrong in the past.
Now I first saw a rather tempting, but failing idea, and after some more thinking I found the elegant solution, which involves a beautiful checkmate.
Here it is as a puzzle first, for you to try :