Composition

Backbone
8-14 Valkyrie
10-18 Hog Riders
10-15 Wizards
5+ Wallbreakers

Support
0-4 Witches
0-2 Golems
0-1 PEKKA
0-4 Healer

Spells
Varies but for Th9 players it always consist of at least 1 jump and 1 rage. Th10 players typically also carry a freeze spell or two. 

Pros
Extremely effective vs Th9 and premature Th10
Hits hard and fast
Valkyrie and Hogs complement each other well
Offers a variety of troop deployment strategies

Cons
Extremely DE intensive and relies very heavily on one barracks
Timing is huge, miscalculations can result in losses
Troops that make the backbone of this combo are very trap vulnerable 

Selecting a Base
Honestly Valkyrie N’ Hogs isn’t so much about base selection per se as it is selecting the right deployment strategy for a particular base. Selecting the right supporting troops for a clan war is also very critical. What I can tell you is that Valkyrie like compacted cores and that is their primary job, usually, in this composition. Still either witches or healers can help you tackle spread out bases. If the base is all spread out (even the core), then this is probably not the best strategy.  

In terms of when this strategy is at its peak, I’d say Th9. Valkyrie and Hogs together can demolish a Th9 base pretty easily. If you loved hogs before the giant bomb change, this may be a way to bring your hogs back into the fold. At this level you can use healing spells or even healers to turn either unit into a high DPS fast moving tank. Premature Th10 bases are also very vulnerable to this combo because hogs will chew through neglected defenses pretty fast.  

When tackling maxed out bases more thought will be required and planning. Healers are a poor choice against th10 for 2 reasons. The most obvious one is multi-target infernos. But after using this composition for a while a bigger problem really is that healers don’t have a 5th level. They just don’t keep up with the DPS of maxed level defenses. Golems and Witches become the supporting troops of choice. With those units supporting your Valkyrie/Hogs you can tackle most bases with the right strategy and deployment.

Consider the CC carefully. It's placement and layout are critical for troop comp and attack angle.

Examples of Valk n' Hog Comps
[link]http://youtu.be/I0iGxx-O00w?list=PLqrAQwazAOaNUfs6Ork3EJ-Z1StjAH4Sa[/link]

Attacking – 
Before I continue this is a difficult strategy to master. Execution can mean the difference between 40% and 90%. It can pack a wallop but requires skill.

Fried Chicken's Th9 Guide - http://www.reddit.com/r/ClashOfClans/comments/2srviy/strategy_th9_valkyriehog_combo_a_3_strategy/ 

3 Stars on Advanced Th9 Bases - http://www.gadihh.com/valkyrie-attacks

Attacking is different depending on what sort of base you’re looking at and how you choose to deploy these units. So instead of trying to type one section on deployment I will break it into the different techniques you can use depending on your objective. 

 

Th8 Variant
 

The V maneuver
This is a technique I favor and is a great one vs th9. It's more tricky vs th10. I start the attack with a lure, either sparing some hogs or bringing along some giants, and draw the CC to an undefended space on the map. I then deploy witches and wizards to take these units out. It’s not a bad idea to have a small handful of barbs and archers for distractions at this point. The Valkyrie trick is also a good option.

I then deploy my tanking unit to distract defensive fire. I usually do this a little left or right of the witches, since they provide good distractions. Vs Th9 and below it’s not 100% necessary to have a tanking unit, as Valkyrie with the heal spell do pretty well.

I will select my location to send the Valkyrie in depending on the base layout. Typically I will send my Valkyrie into the core. In this scenario I will look for the best direct route to the core, somewhere where placing 1 jump spell get me where I want to go. But sometimes I will allow my Hogs to do the work of clearing out the core. I will do this if buildings are tightly packed in larger compartments around the core. Valkyrie do best against tightly packed compartments. I will also try and send my Valkyrie in a location that potentially has many giant bomb traps. Valkyrie aren’t particularly vulnerable to these traps and do much better than hogs against them. The Valkyrie should also deal with the Queen. For high level heros a PEKKA is a good addition.

Once my Valkyrie have the defenses occupied I will send in my Hogs so they crisscross with my Valkyrie. They will destroy a defensive side of the base that has not been touched. I will then try and time one healing or rage spell for when these two groups cross paths. For this particular maneuver I favor 1 jump, 1 rage, 1 freeze and 2 heal. Don't worry at th9 if you need one heal to counter a GB.  

If you get the timing right, you essentially get twice the spell for the price of one. The other reason I developed this strategy is that Hogs and Valkyrie have very different strengths. Valkyrie hit hard and fast but quickly petter out as they run into walls. Hogs on the other hand, jump walls but lack the HP to sustain much damage. Valkyrie also have a nasty habit of getting themselves bottled in the core and then getting “stuck” as defenses from all side fire on them. Hogs can easily clear one side of this bottle, and then proceed to easily and effortlessly continue past the core. This also buys Valks enough time to break out of the core.

After this it’s all about spell timing. I typically use rage to get my Hogs past the queen if Valks didn't neutralize her and try my best to have at least 1 heal spell available for when the core is down. Either a rage or a heal will work when the two groups crisscross, but the better the timing with your spells the more damage you can do. Ideally you want to be dropping your healing spell so that units in critical health recover most if not all of their HP. With your hogs, you also want to keep a close eye on possible giant bomb locations and save health for a possible trap.  

Please note that this strategy will fall apart if the Valkyrie cannot survive very long. This is why Golems are necessary verses Th10. However, verses Th9 HoVaPe or even He-HoVa will also work well since you can use healing spells and the overall DPS of the defenses is lower.  

Verses mid to advanced th10 requires more caution. You can not afford to trigger a GB while the hogs clear a side. It's better to have a second golem and to deploy him as the main force hits the core to attract flanking fire. While defenses are busy hogs can take out point defenses on a walled off side. Note this isn't my primary strategy vs th10.

Cavalry Charge
For th10 this is a blitz. If the base offers a direct path to the core and the big guns are clustered together, then you can use rage/freeze to basically do critical damage in 8 seconds. I use 2 Golems at th10 for this attack and open up like a GoViz but consider defense pathing for hogs as well. I only lure if it's an easy lure.

Centralized heros are better along with heavily centralized important defenses. Also room to set up the attack is necissary, CC triggering too early will mess you up.

I always try and get my Valkyrie into the core with this strategy. I want them occupying defenses and any CC in the way.

If possible I keep a golem near the surge of my attack. I use it to trigger the CC from one point, so I get a straight pull. As long as I can get the CC drawn out in a clump my Valks will eat them alive. If inside the core when they meet so I can add freeze on top, perfect.

When it comes time to unleash the hogs, so to speak, I time it so that the hogs reach the core about the same time as my Valkyrie. Pay careful attention to defenses that make a direct line to the core, they'll help you hit the core hard. I don’t cluster my hogs, but spread them out in a tight line. Or I send a few slightly ahead of the pack. Once they hit the core I will either drop a heal or rage spell. Freeze comes into play for inferno fire. With this maneuver, your royals, Valkyrie, hogs and witches should be colliding with the core roughly the same time. This means as long as you can take down/freeze 1 inferno your heal spell should still be effective due to the number of units in play. Activating your king’s ability at this time is a particularly good way to distract the inferno as well. For higher level th10 bases it is better to drop the heal for another rage. Aim to do as much damage as you can as quickly as you can as a strong th10.

Tine the 1st rage for as you collide with the core and the second as you exit. At th9 you can save a spell to keep momentum going. 

The Hog Lure
Inventor: ZenCoC
http://youtu.be/7l2Ip-x-GuE

This is a strategy developed by ZenCoC and is typically used with a heavy witch composition. This strategy uses hogs in the opening of the attack rather than as a 3rd wave. Bases that have point defenses that aren’t covered by the heavy hitters; infernos, x-bows, and well protected wizard towers, are vulnerable to this tactic. In particular if tightly grouped.  

In its pure form a rage or heal is dropped in the opening of this attack and a portion or all of the hogs (10-12) are dropped to clear defenses and trigger the CC. Depending on the layout you may or may not spread the hogs out, but the goal is to clear some defenses while luring the CC at the same time. After the CC is eliminated drop a wizard to clean up the weakened area.

Typically a full pull is pretty easy with this strategy but you’ll want to careful consider the location of the pull. Triggering a set of double bombs would leave your hogs nothing but bacon.

The next step is to get the CC troops in the open and clumped up. The Valkyrie trick or witches can kill the CC but you must have fodder. I frequently make the mistake of deploying witches without distracting the enemy CC. If you do this the enemy CC will ignore your skeles and beeline to your witches. For either troop drop a barbarian or 3 to get the attention of the CC. This give witches time to spawn skeletons and valkyrie time to swing. Deploy witches with wizard support to eliminate enemy CC. Note if your losing units other than fodder or a minor loss, you did this wrong.

Next deploy a golem to tank damage from the defenses left or right of where the hogs cleared out defenses. This Golem is to protect wizards as they clear distracting buildings. Get the Golem inside the base. Make sure to get any free buildings left by the hogs with that solo wizards.

Deploy Valkyrie and BK so they make a direct line towards the core. It’s best to choose an attack location that restricts the Valkyrie’s movement this way, having heros in the core will help significantly with this. Drop a jump spell to get your Valkyie to the core quickly. 

Once in the core drop freeze spells to lock up the infernos and if possible a hero as well. Drop a rage spell once you’re Valkyrie have breached the core to accelerate the mayhem. Make sure to save a few wizards or train some archers to pick up easy buildings once the core is done. With this strategy it’s easy for your units to become stranded in the core. It’s also sometimes a good idea to save your king for clearing outside buildings if the core will not yield a high enough percentage for the 2 star.

Witches are best in thus combo. With a cleares side and Valks destroying the core, these gals can keep your AQ going.

Hadif Breaks Down a Th9 3 Star
 

Hafid Video Link 2: https://youtu.be/Yv2CS-SloE8

Youtube


Nigel Momongan from Youtube - Various Valkyrie and Hog Replays

ZenCoC
https://www.youtube.com/watch?featur...&v=6aMQ6OkHnlE
http://youtu.be/3uEs6MBMNZw
http://youtu.be/UHHRmZBdWRA
http://youtu.be/uYDgceqtbnU

Variations
Th8 - 1 Golem, 1 PEKKA, 10 Wizards, 6 Valks, 10 Hogs - wb and fodder to flavor - 1 Rage, 2 Heal

Th9 - 1 Golem/Giants, 8 Valks, 18 Hogs, 8 Wizards and WB/fodder
Fried Chicken's Th9 Comp - 2 Giants, 1 archer, 1 Wallbreaker, 3 Wizards, 15 valkyries, 15 hog riders - Spells- 3 heals, 1 jump.
Slaskio's Comp - 12 Hogs, 8 Valks, 7 Wizards, 4 Witches, 10 WB - Spells - 2 Heal 2 Rage, Golem in CC

Th10 - Cavarly Focused - 2 Golem, 1 PEKKA, 7-9 Valks, 12 Hogs, 10-13 Wizards, 6 WB and fodder 

Th10 - Hog Lure Focus - 1 Golem, 2-4 Witches, 10-15 Wizards, 7-9 Valks, 10-15 Hogs, WB and fodder