Ah...Valentine's Day. The holiday that's all about amore, roses, and chocolate. And, while the first two things are fabulous and great, I'm concerned with the chocolate today...specifically how to chop chocolate.
Choose a serrated-blade knife (a bread knife works especially well), and begin at the corner of the chocolate with the knife angled slightly outward. Then using a smooth back and forth sawing motion and pressing only as hard as necessary, begin to whittle the chocolate into almond sized pieces. Once you have cut one corner down sufficiently, rotate the chocolate and begin on a new corner until all the chocolate is chopped into fairly uniform-sized pieces.
If you find that the chocolate seems too soft or starts to melt, place it in the refrigerator for about 15 minutes. You can also do this prior to chopping to make the chocolate even easier to work with.