It will be good if we mention right at start that we’re going to discuss about not just two, but 5 movements altogether. For, the roots of the calibre 8215 go down to the calibre 8205 and it branched out to become the calibre 821A later. The calibre 8205 also has another descendent – the 820A – which is its decorated version. Or, you can simply say that it is the day/date version of the 8215. It won’t be fair if we leave them out of this discussion.