"A 6 man link? Lazarus0909, have you gone mad," you might say. After all, there's no such thing as a 6 man link. Fireteams, by their very nature, are capped at 5 (or fewer) members. But that doesn't mean that, AVA permitting, you still can't build you army list with one.
By now you might be scratching your head confused, but we're actually dealing with an interesting concept that crops up every now and then and can be a very viable list building strategy. The notion is actually surprisingly simple - include a "spare" link team member in your list, so that if one member in the link team goes down, you can reform the link at full strength with the surviving 4 members + the spare to make a full strength link again.
Note - You can also adopt this same approach for other smaller link teams like Haris, Triad, Enomotarchos etc, but it tends to see the biggest benefit with 5 man link teams simply due to them having the biggest bonus at full strength and representing the smallest investment for the extra member vs. the cost of the rest of the link.
It's certainly an interesting idea that can prove to be popular for sectorial builds that do a lot of heavy lifting with their link, but let's examine some of the restrictions first before we can begin to see the benefits.
Before we can consider looking at running a "6 man link" in our sectorial army, we have to make note of a couple of limitations that need to be addressed.
1. AVA - Certain sectorials simply cannot run a "6 man link", because it is impossible to field more than 5 members in a single army (don't forget about Spec Ops and Characters though that might help you overcome this limitation). This is the first and biggest hurdle because it is totally insurmountable. For example, in Military Orders one could run a 6 man link of Order Sergeants, but Fusiliers are capped at AVA 3, so even with Bipandra AND a SpecOps, it would be impossible to field 6 of them.
2. Combat Group - It goes without saying that, most of the time, you want all 6 members in the same combat group. Most of the time, you won't be wanting to spend a command token to move the 6th member into the other pool AND another to reform the link at full strength, so it's usually important to have the link and the spare in the same combat group. Exceptions do exist (e.g. Free Agent) but this is definitely something players want to think about in terms of list construction, because sometimes you really want your link to share a pool with 5 other models in your optimal setup, but bumping it up to a "6 man link" would only let you fit 4 others in their pool. Not a deal breaker, by any means, but something at least to think about.
3. Cost - Cost is either a massive problem or a tiny obstacle depending on the link in question. For some big heavy infantry links (e.g. Mobile Brigada), they might have a high enough AVA (6 in this case), but each new member is a minimum of 33 points, making the cost almost impractical. For other links, especially those consisting of line troopers, the cost of a spare can run as little as 10 or even 6 points (e.g. Grunts in the same sectorial). This is an important consideration when building a list, because to some setups the cost of adding an extra member is almost trivial, whereas others find it nearly impossible.
4. Positioning - This is probably the most subtle of the hurdles, and yet it can be one of the biggest if you've successfully overcome the previous stages and haven't thought about this section. For instance, if your 5 man link plans on rushing forward and closing with the enemy as quickly as possible, then any spare is likely going to be left in the dust, and might represent a significant order investment to catch up with the link before reforming it. If however your link is basically a firebase that plans on lurking around your own backfield, then the spare probably won't have far to go (if at all) to get into ZOC and reform the link. This is why "where the link plans to be" is extremely important, because you need to make sure all 6 members are near each other if you plan on reforming at full strength.
Or to sum it up - there's no use having a spare tire if you left it in the garage!
Okay, so we've discussed that there are a couple of limitations to this approach, and indeed it isn't even an option for every link. Fair enough. But, once we've made it this far, we can look at some of the awesome advantages:
1. Maintaining the link bonus for as long as possible - This is the big one. Having an extra spare member of your link means that when you inevitably take casualties, you can reform the link at full strength. In many cases, if your opponent hunted down you link leader and broke the link anyway, this isn't costing you any extra resource in command tokens to reform at full strength compared to reforming at a smaller size with the survivors. A lot of people also only think about reforming the link at the 5 man bonus, but it's also worth remembering that in situations where you're taking many casualties (e.g. 3), having a spare makes you that much more likely to still have at least say, a Haris, whereas a normal 5 man link would by now be reduced to a duo and have significantly less shooting potential.
Example - Hafza. In Qapu Khalqi, Hafza are a cheap and effective way of filling out a link team for maximum bonuses while costing less than just about every other real link team member in comparison. Because Hafza can link with just about anything, this lets you keep link bonuses up for as long as possible even on expensive links like Janissaries, while moving up another real Janissary to take the place of one of the fallen would cost considerably more. In the meantime Hafzas of course also have uses as a decoy, which of course leads us to...
2. You were taking the extra model(s) anyway - This is another very compelling reason to take an extra member. Great candidates for this are things like backfield line troops with Hacking Devices (for things like supportware), extra specialists/heavy weapons (when you want more choices in the link than your 5 man allows, or where the model is perfectly useful on its own), or the best example of all - the model is your Lt. In these cases, having a "6 man link" is very viable because the extra model doesn't represent a cost that you weren't already willing to pay, and it helps enormously if that model has something to do on its own while waiting around for the link to take casualties.
Example - Lone Myrmidons. For 16 points with a Chain Rifle, Myrmidons are fantastic on their own as a cheap and effective source of smoke that you sometimes want access to without activating the rest of the expensive Myrmidon link or just to have on a different part of the table. These full Myrmidon link teams can often run into three-figure sums of 100pts or more once you factor in the characters, so the Myrmidon represents a fraction of the cost to maintain the strong link bonuses, but also has plenty to do even if it is never needed within the link itself. Finally we should look at a really big plus, which is
3. It lets you leave the Lt behind (and move up again with their order) - As part of #2, in many cases you might run a 5 man link normally with the Lt making up one of the 5 members. However, by having the Lt as the 6th man, this lets the link wander off a bit more freely (no risk of exposing the Lt) and lets the Lt stay back in relative safety. Then, once the link takes inevitable casualties, the Lt can move up with its own order and potentially reform the link at a greater strength. This is a particular plus on turn 3 or if you have Chain of Command, as even if the Lt gets killed doing this endeavor, it won't matter because you don't have to worry about Loss of Lt.
Example - Line troops (e.g. Ghulam, Fusiliers, Alguaciles, Grunts). Basically just about anything with total AVA, and this is usually the most popular case for the "6 man link" due to the relative popularity of the cheap but fragile "cheerleader" backfield Lt. The relative cheapness of the overall package makes taking extra members an incredibly cheap prospect, and this lets you leave the Lt cowering someplace safe at the back while the link presses on ahead as discussed above. In many cases, the sixth man can also be just a simple specialist, who is often more than happy to babysit a backfield objective for minimal cost or even coordinate with other models doing some suppressing fire (something the link members can't do) while it holds its own, and then join up with the others later on.
There are just a few of the examples where you can put this application to good use on the tabletop, but I'm sure you can think of many other really good setups out there.There are a number of lists where it might be worth grabbing a spare "extra member" for your full size link teams to maintain their benefits for as long as possible, and I urge more of you to give it a try on the tabletop if you are looking to leverage the bonuses for as long as possible while maximizing the utility of your other models.