Vi is a strange tank set up. She has a recurring shield effect based on her HP which makes her more survivable. She has a passive ability that damages based on your opponent's health which makes her a good anti-tank choice. She has a wide cone attack that will one shot an entire creep wave regardless of size. She will leap on enemy carries like a crazed spider monkey.

The Wal-V set up is built around being just that: a flippin' wall. Vi's function as Solo Top is to not die, and ensure your opponents never get the protection of their creep. If someone tries to tower dive, she punches them back into range of the tower and knocks them up with her ulti. The responses to Vi are either give her the lane because you're not pushing it(at which point Vi is free to push the lane to her heart's content) or bring the thunder by trying to 4v1 her... which will meet with varying degrees of success.

This guide is a work is progress based on what I've gleaned by experience.

Early game is where Vi really shines. Eschewing shoes shall shake assurances of staple strategies. Additionally, always acquire ample alliteration along alien answers. The point of forgoing shoes is simply because you don't need them as much as you need the sustainability of the flasks for early game walling. Even early 2v1 you have the sustainability to let the tower kill your opponents. Running away marginally faster wouldn't save you, but the health and mana from the flasks will get you into the protection of your turret. By the time you run out of your six flasks and need to B, you have the money for your Avarice blade. Wouldn't Larfleeze be proud?

The rest of early game involves sitting under your tower and calling our MIAs, or "pushing" to get them to engage in preparation for a gank from your jungler. It's a quiet, peaceful existence of punching waves of minions into oblivion and letting your gold accumulate.

The concept seems silly, but at its heart makes sense. Numbers matter. If a player D/Cs, then the opposing team has a numbers advantage to such a high degree that they will usually win... ceteris paribus. The idea behind the wall is that, for the early game at least, you're rocking a 6v5. You're turning your tower into your 6th player. Trollcrank plays a similar game, but there are two big differences: Vi doesn't have the grab, and Trollcrank becomes a support character. The Piltover Enforcer starts off fairly passive, a Vi-lette if you would... but Vi blossoms into an immortal succubus once she hits mid game.

By the time you hit midgame, Vi should be the picture of Freudian repression. She's been getting bonus experience, and bonus gold while holding a lane all by herself. She's big, she's fed, and she's ready to make up for lost time. Once it's time, let the genie out of the bottle and wish for an ace.

Once your Atmog's set up is good to go, you're ready to go out and visit the world. Stop by Blue Buff and get fueled up for the road. The midgame strategy I enjoy is the exact opposite of what you did during the Vi-lette portion: You solo push top. You make a racket, and force them to deal with you. Instead of the standard "Juke and Ambush" that one sees to readily used, this method requires merely an enemy team that doesn't want to lose a tower instead of an enemy team not bright enough to see that they're about to get ganked.

At this point Vi should have 3k+ HP. between her masteries and her Warmog's regen, Vi can tank a tower. Vi joins the creep and waits for the inevitable enemy assault in defense of their tower. As long as Vi is the first one to hit the enemy, the tower will punish her so your team has carte blanche to beat down any champ they want to. The only problem with the tower dive gambit is that your team has to be bursty. The enemy has to die within the time it takes the tower to kill Vi. Still, she's ahead of the power curve so she can survive a lot more than any of your other people. The enemy has to stop their tower from being taken. When properly executed, it works beautifully.

There isn't much of a change from Mid to Late. The team fights become more important late game, and Vi's role as tank/MasCas Enthusiast become more focused, but it doesn't change the overall point of things: Vi leads the charge, makes the enemy deal with her, and runs down potential survivors.