In our modern way of teaching Italian rapier, the default is generally to teach the passing step with the left foot remaining turned out. This allows for the maximum amount of reach in a single step as it allows you to continue forwards while staying profiled and not having to do much to turn the hips or the shoulders. Where do we get this from? Is this in line with what we see in the manuals? Let’s find out.
To start off, let’s look at the greatest author (fight me) on the subject, Nicoletto Giganti. In his manuals, while we see the left foot starting off turned out, nowhere do we see this as the ending position for a passing step. In every completed passing step (there’s one image with the left foot in the air that I’m not counting here), we see the foot turned forwards. Why might he be doing it this way? There are many answers to this question, but let’s consider just a few here today.

The question you likely have rattling around in your brain is, “Well he only shows this to us one way. Is that what everyone else did?” The short answer is, “no.” To flesh that out a little bit more the answer is actual yes, with the occasional instance of no.
We currently have two books written by Giganti, although he does make reference to a possible third. While his first is much more well-known (and is overall just a much better book), his second book does show us a variety of instances where passing steps are employed. In none of these, though, do we see the left foot ending turned out.
“Well what about everyone else?”
I am glad you asked. In fact, I am even more pleased by the fact that you are making sure to broaden your own education by not limiting yourself to any one resource. Let’s take a look over at Capoferro. Overall he seems to pass less often than Giganti does. When he does pass, he is doing so the same way as Giganti in almost every single plate.[1] Occasionally we even see the foot turned with the toe pointing inwards as for instance we see in plate 12.

We do, however, find a couple instances that break the mold. First, on plate 11 we see depicted a passata sotto, an action that involves ducking under your opponent’s sword as you pass forwards.

Notably, this is not an action we see depicted anywhere in Giganti. Giganti has two plates in his second book that each depict a sbasso,[2] a lunge that involves ducking under your opponent’s sword, but never shows us a passata sotto[3].[4] Now, why might Capoferro be encouraging a turned out passing step here, but not when we’re more upright? The big reason that come to mind are that you have already succeeded in getting out of the way of your opponent’s sword and that you don’t need to resist any sort of parry. The passata sotto is an attack in absence where instead of gaining your opponent’s sword and then striking through, you have instead gotten your body entirely out of the way and are now just striking into an open target. At this point all that matters is not falling over and making sure your point can reach. So, by turning the foot out Capoferro provides us a more stable base while extending our measure, all while not having to worry all that much about structure.
These two are also the reasons that Fabris, generally the most detail oriented of the bunch, gives us in his explanation of how to pass low while striking in seconda on plate 8 of his book.

He tells us that passing in such a way will actually make any more steps forward much quicker. Fabris also defaults to having you continue going forwards once you have struck your opponent, whereas Giganti generally wants you to recover and then strike three to five more times as you opponent stands there in shock.
Continuing on, we see the foot turned out when passing in quarta even though the upper body isn’t bent over to the same degree, although still more so than we generally see in Giganti.

This method of passing forwards with the left foot turned out continues to be employed for the vast majority of his book.[5] We do see a few plates that depict that clearly depict the left foot in front with the toe pointing forwards, but these are almost entirely left foot forward guards as opposed to ending positions for passing steps. The only plate that clearly depicts a pass with the left foot ending up pointed straight Is all the way in the back in the section of how to respond to attacks with a dagger while you are unarmed. We see this same thing happen a little earlier in the book with disarms, as well as a throw, against the sword.[6]

Notably, we no longer see the quintessential Fabris posture depicted here with the pronounced hip hinge and instead see fighters standing straight up.
So, when should we turn our foot out on the pass? It would seem that the answer is that when standing more upright, as in Giganti and almost all of Capoferro, we should refrain from turning the foot out. However, if we are someone who tends to keep their torso lower to the ground, it seems that turning out is indeed the answer.
Peering over at the earlier Bolognese material, we see the foot being turned out on the pass if it’s a discordant cut. This same logic doesn’t seem to translate to the thrust here, though. While Giganti doesn’t show us many passing steps to the inside, when he does he still keeps the foot turned forwards.

Fabris shows us the turned out pass with the blade oriented in all four guards of the sword. Fabris maintains his foot turned out orientation both when his upper body is folded forwards as well as when it is folded off to the side. Giganti hardly ever leans off to the side with his upper body and is only seen doing so on the lunge and not the pass[8], as part of an inquartata[9], or as part of a void as against an opponent coming in with the feet planted.[10]
A slight exception to my overarching theory so far is that we do see a rather bent over upper body while keeping the left foot pointed forwards while half-swording. It is important to note, though, that although the body is being bent forwards you are still above your opponent’s sword here and are pushing downwards instead of trying to disengage your body underneath.

Going back to Capoferro, we see the same thing happen again where instead of half-swording, he presses down on his opponent’s arm with his off hand and thrusts from underneath with this sword. In this play again the body is kept far above your opponent’s sword and thus we keep the left foot pointed forwards.

The piece that ends up breaking the proposed theory is what shows up a few pages later. Here we see Capoferro passing with the foot mostly, although not entirely, turned out without his body being bent over all of the way.

Draw your attention to how far his sword is sticking out the back of his opponent’s head. Most of the time there’s a generous serving of steel poking out the other end, but in this instance there’s only a little bit, implying that this action is done at the edge of his widest measure.
Going deeper into Fabris also reveals to us a couple exceptions to the left foot being turned out on the pass.

Here we see that the primary concern is with getting the dagger across the body instead of on maximizing reach. The sword here is already a decent distance through the opposing fighter even after going around the dagger and having the arm bent.
So, while there seems to be a large overlap between how far you bend over and how turned out your left foot is on the pass, they seem not to be purely concentric circles. While we could dismiss these last few examples as just the exceptions that prove the rule, that answer just doesn’t do it for me. There’s a reason each of these plays was put into texts we’re still reading four hundred years later, so clearly there’s value there. After talking to a few friends and getting to try things out in the real world, I was able to figure out something else that seems to explain more of what’s going on. While turning the foot out definitely helps keep balance for some of the more extreme front-bending postures, what it does regardless of back flexibility is that it allows for a wider measure and provides more resistance against anything moving in along the z-axis. We see this foot orientation paired with keeping the hips turned such that the right hip stays in front, keeping the fighter more profiled and extending their reach along that single line. On the other hand, turning the foot forwards and squaring the hips up provides more resistance for pressure on the x-axis. This helps better fend off cuts and counter-finds, as well as helps provide more stability while passing off-line.
At the end of the day which way should we turn out foot on the pass? In Fabris the emphasis seems to primarily be on getting your body out of the way of your opponent’s sword and then maximizing your reach in order to hit them. We see the foot turned out even when the pass isn’t particularly deep, which is reflective his wider use of voids than some of the other masters as he would rather deal with as little blade on blade contact as possible. What he leaves open instead is how far forwards he needs to step. By leaning farther forwards he makes it easier to get his upper body out of the way as well as extends the reach of his attacks. Giganti, on the other hand, sets himself up to deal better with lateral resistance from his opponent’s blade. Especially on the outside line his concern is with intercepting his opponent following up with a cut.[12] As well, his default lunge in seconda is fairly squared up, which sacrifices a bit of measure but in turn provides more lateral stability for keeping his opponent’s tip outside of his silhouette. He tends not to bend his body as far over when he lunges, as after a certain point hinging forwards makes it harder to provide resistance against a riposte. Thus, by avoiding these positions he ends up not really needing to turn his foot out on the pass for added stability and can instead keep it pointed forwards more easily opening up cross line and off-line steps. While none of these authors entirely eschew one strength for another, we can learn a lot from how much they prioritize one over the other.
[1] Capoferro plates 8, 9, 12, 13, 20, 31, 33, 34, 38, 40, 41, & 42.
[2] A low line lunge.
[3] Lierally “pass under.”
[4] Giganti book II pages 84 & 86.
[5] Fabris plates 37, 38, 39, 40, 41, 42, 45, 46, 105, 129, 132, 136, 137, 141, 145, 148, 159, 162, 167. 169, 171, 173, 175, 176, 178
[6] Fabris plates 180, 181, 182
[7] Giganti Book II pages 50 and 54
[8] Giganti Book II page 80
[9] Giganti Book I plate 7
[10] Giganti Book I plate
[11] Capoferro plate 18
[12] Giganti Book I plate 10