Interpreting Talhoffer is quite difficult. With only small fragments of text to accompany the images one has no choice but to consult other sources in order to understand what is actually happening.
The fencer is in vom Tag or “From the Roof”. In the following images you can see illustrations of the same-said guard by Sutor, Meyer, and Mair. It is characterized by both hands being will above the head and the point angled back.
It should be noted that this isn’t the only interpretation of vom Tag. In the Danzig and Solothurner versions the point is more upright than back, and Danzig doesn’t even hold the blade above his head.
Since we are discussing the high guards we would do well to compare it to Marozzo’s Guardia di Testa or Head Guard. Both allow for powerful cuts from above, but di Testa has the advantage of protecting ones face.
One should not jump to the conclusion that Guardia di Testa is necessarily better than vom Tag. Cuts from di Testa tend to be fairly short with most of the work being done with the quick leveraging action that is unique to two-handed swords. By contrast, vom Tag encourages cuts that are thrown with the whole body so that one sinks low much like one would do in a lunge.
Note how vom Tag is generally shown with the left foot forward and di Testa with the right. One can easily envision closing range by transmuting from vom Tag into di Testa by taking a step and lowering the hilt. Don’t do that. As tempting as it may be, both Marozzo and the German’s would think it too dangerous to close range without the accompaniment of an attack or feint. If you just take a step then you will probably find a sword under your arms and in your face.
If one is at a wide measure, prefer vom Tag for its extended range. In a narrower measure use Guardia de Testa for its defensive posture and quicker cuts.