SHU Formations
There really isn't any formation that can win it all. Formation and position of Heros must change according to your opponent you face. Just like playing chess, only certain character will be in your favor to move due to restrictions and what the character can do. In this game there are many formations in play, so now it depends on who or what attack type you need to focus on first. In a nut shell, TCA is the underlaying attack hero in every country, so ARROW form (TCA) is form that you need to focus on first.
In later map where you run out of silver to enhance on defense, TAPPER (EVA) formation will be use to lessen damage, but nevertheless your damage will also be reduced.
Some might also use CRESENT form (CRT) to deal high damage in FS. Also, this form enable player to position attackers in a very different format to be strategic against appoints attacks.
During the final part of the game, you will start to choose your attack type with TCA as your foundation attacker. If you choose to have WY to be your main hero then SINGLE LINE form (COMM ATK) will be your next focus of formation. WY can do quite a great ordeal of damage if he is equipped with Snake Spear at study lvl9 in CRESENT form (CRT). I have personally tried WY in 7 STAR formation (Counter) with lvl4 counter flag. That was the first time I saw WY attack more than 2 times in one round facing high level heros.
For those who choose to use Zhuge Jin ( WU hero ) or Zhou Yu ( WU Hero), it will be best for them to focus on the 8 TRIGRAM (STA) formation that will be very useful in PVP and Country battle against WU or WEI. But there is a downside to STA formation. STA heros cannot really deal high damage in map battles. Hence they will still need to depend on their basic attack, TCA.