aelf
Ashen One
Many of you might be wondering what's the point of building the Great Wall. It's not a modest wonder, costing 300s. Certainly, the barbarian bonus is useless. And who wants to get a 20s improvement for free, esp since it's gone when your towns grow above 6 pop (enabled by the very technology that unlocks the Great Wall)? The wonder expires after Metallurgy too. All in all, it seems to be a bad deal.
Well, there's a different point of view. If you are a militaristic civ planning to embark on that early middle age campaign of massive expansion, it might be useful to consider building this wonder. It has worked on Emperor, so I'm pretty sure this is a viable option, though higher difficulty settings might present challenges I can't foresee.
So why the Great Wall? As a warmongering militaristic civ, what ancient age wonder would you choose to aid your game plan? Of course, the best is to get the powerful SoZ. I'd advise that you take that over the Great Wall anytime, unless you love challenge. But you're not blessed with ivory that is within reach in every game. Would you save for Sun Tzu, just one tech into the middle age? That seems great for purposes of warmongering. But why erode your civ's inherent advantage? As it is, you enjoy cheaper barracks. By building Sun Tzu, you are spending shields to eliminate this advantage, shields that could be spent on addressing your civ's weaknesses. It's better to shoot for Leonardo's Workshop since your (likely) authoritarian political system does not produce as much gold for upgrading units, but that's later (probably by then you are well into your campaigns). Why, you might ask, would you want free city walls, which you can build at half price as well? It is percisely because you are unlikely to spend time building them.
In the early middle age, your road to glory takes the form of the formidable knight. You'd likely be concentrating on building him, since he has the same defensive strength as a pike while packing a punch.
So it happens that you make a conquest or two in a turn with your knights, how would you hold that city you've just conquered against the counterpunch an estimable foe? Sometimes you don't have or can't get enough pikemen to that city within that turn. Sometimes your pikemen can't even reach the city within that turn (esp so for Chinese players using fast Riders against enemy cities further into hostile borders). In these cases you risk losing some of your valuable attacking force defending that city. You might even lose that city if the enemy counterattack proves to be stronger than expected. Here, the Great Wall comes to your aid.
While a free barracks building doesn't help your knights survive attacks during the enemy's turn, a free city wall can. If you have the Great Wall, the city you conquer immediately gives you an advantage at defense to help your attacking force survive. Even if you can get enough defenders into the city, you'd want to be concentrating on maintaining your offense without, as much as possible, having to build extra defenders to replace those killed.
After you have survived the critical period right after taking an enemy city, you'd probably not have that much use for walls. That means, while you might want to build barracks later on, you'd probably not waste a few turns on walls. Only the Great Wall can always give you those walls when they are most useful. Of course, you have to balance this with not having your units in that newly acquired city heal as quickly if you are forgoing Sun Tzu in favour of the Great Wall.
As I have mentioned, this gambit works well for Chinese using Riders. Japanese Samurai become one step closer to invincible, while Arabian Ansars and Mongolian Keshiks can finally stand on their own. Moreover, Arabs can benefit tactically like the Chinese, while Mongols can more safely conduct an invasion across unpathed mountains inaccessible to slow defenders.
On the strategic level, a warmonger with the Great Wall is, needless to say, only made stronger during the important early middle age campaigns. Other civs would be less willing to or attack (or, failing that, less successful at attacking) while you conduct your war against a neighbour.
Naturally, terms and conditions apply. The Great Wall only pays for its cost if you are chielfy concerned with overland campaigns (since the wonder only works for cities on the same continent) in this phase of your game and are facing worthy opponents. The first time I tested this I found out that the opponents I faced on my continent were so feeble they couldn't even stand up to my swordsmen. I didn't face any counterattack worthy of being blunted by walls to save my attacking forces.
*One other potential problem that I almost forgot to mention is getting a GA with the Great Wall when you had hoped that your Riders (for example) will give you that nicely-timed, non-despotic middle age GA. But from my experience, it's not so bad. Getting a GA with the Great Wall enables me to get to monarchy quickly and greatly helps with unit production as well as some basic infrastructure construction. When the time comes for me to launch my chivalry campaign, I am better off than I would be had I not gotten a GA earlier, and I appreciate the edge it gives me in such a crucial period.
Feel free to express any comment/opinion regarding this
*added later
Well, there's a different point of view. If you are a militaristic civ planning to embark on that early middle age campaign of massive expansion, it might be useful to consider building this wonder. It has worked on Emperor, so I'm pretty sure this is a viable option, though higher difficulty settings might present challenges I can't foresee.
So why the Great Wall? As a warmongering militaristic civ, what ancient age wonder would you choose to aid your game plan? Of course, the best is to get the powerful SoZ. I'd advise that you take that over the Great Wall anytime, unless you love challenge. But you're not blessed with ivory that is within reach in every game. Would you save for Sun Tzu, just one tech into the middle age? That seems great for purposes of warmongering. But why erode your civ's inherent advantage? As it is, you enjoy cheaper barracks. By building Sun Tzu, you are spending shields to eliminate this advantage, shields that could be spent on addressing your civ's weaknesses. It's better to shoot for Leonardo's Workshop since your (likely) authoritarian political system does not produce as much gold for upgrading units, but that's later (probably by then you are well into your campaigns). Why, you might ask, would you want free city walls, which you can build at half price as well? It is percisely because you are unlikely to spend time building them.
In the early middle age, your road to glory takes the form of the formidable knight. You'd likely be concentrating on building him, since he has the same defensive strength as a pike while packing a punch.
So it happens that you make a conquest or two in a turn with your knights, how would you hold that city you've just conquered against the counterpunch an estimable foe? Sometimes you don't have or can't get enough pikemen to that city within that turn. Sometimes your pikemen can't even reach the city within that turn (esp so for Chinese players using fast Riders against enemy cities further into hostile borders). In these cases you risk losing some of your valuable attacking force defending that city. You might even lose that city if the enemy counterattack proves to be stronger than expected. Here, the Great Wall comes to your aid.
While a free barracks building doesn't help your knights survive attacks during the enemy's turn, a free city wall can. If you have the Great Wall, the city you conquer immediately gives you an advantage at defense to help your attacking force survive. Even if you can get enough defenders into the city, you'd want to be concentrating on maintaining your offense without, as much as possible, having to build extra defenders to replace those killed.
After you have survived the critical period right after taking an enemy city, you'd probably not have that much use for walls. That means, while you might want to build barracks later on, you'd probably not waste a few turns on walls. Only the Great Wall can always give you those walls when they are most useful. Of course, you have to balance this with not having your units in that newly acquired city heal as quickly if you are forgoing Sun Tzu in favour of the Great Wall.
As I have mentioned, this gambit works well for Chinese using Riders. Japanese Samurai become one step closer to invincible, while Arabian Ansars and Mongolian Keshiks can finally stand on their own. Moreover, Arabs can benefit tactically like the Chinese, while Mongols can more safely conduct an invasion across unpathed mountains inaccessible to slow defenders.
On the strategic level, a warmonger with the Great Wall is, needless to say, only made stronger during the important early middle age campaigns. Other civs would be less willing to or attack (or, failing that, less successful at attacking) while you conduct your war against a neighbour.
Naturally, terms and conditions apply. The Great Wall only pays for its cost if you are chielfy concerned with overland campaigns (since the wonder only works for cities on the same continent) in this phase of your game and are facing worthy opponents. The first time I tested this I found out that the opponents I faced on my continent were so feeble they couldn't even stand up to my swordsmen. I didn't face any counterattack worthy of being blunted by walls to save my attacking forces.
*One other potential problem that I almost forgot to mention is getting a GA with the Great Wall when you had hoped that your Riders (for example) will give you that nicely-timed, non-despotic middle age GA. But from my experience, it's not so bad. Getting a GA with the Great Wall enables me to get to monarchy quickly and greatly helps with unit production as well as some basic infrastructure construction. When the time comes for me to launch my chivalry campaign, I am better off than I would be had I not gotten a GA earlier, and I appreciate the edge it gives me in such a crucial period.
Feel free to express any comment/opinion regarding this
*added later
I wanted to catapult some GW's. 
. However, in Single Player, AI Wonder Cascading effects would be almost nule. Thanks to my catapults 
.
