Chu Ko Nu (Age of Empires II)

"Chinese unique unit. Archer with mediocre range. Fires large number of arrows very quickly."

- Age of Empires II description

The Chu Ko Nu is the unique unit of the Chinese in Age of Empires II. It is an archer that fires multiple arrows in quick succession.

Only the first arrow does full damage, though. All the other arrows fired deal exactly 3 damage and are unaffected by the target's armor. A regular Chu Ko Nu fires three arrows per volley, an Elite Chu Ko Nu five.

Chu Ko Nu can be upgraded to Elite Chu Ko Nu in the Imperial Age.

Tactics
Chu Ko Nu are usually used in a combination with Monks as healers and Scorpions behind them along with some Villagers. They are great against most close combatant units, especially when facing War Elephants or Teutonic Knights. Chu Ko Nu also do very well when mixed with infantry. Another way to utilize Chu Ko Nu is to use them to protect Castles. In contrary to popular belief, Chu Ko Nu barely increase a Castle's attack. However, due to each arrow having a 0 melee attack (thus doing 3 damage per arrow against Rams), groups of Chu Ko Nu are a great deterrent against Rams.

The Chu Ko Nu have the distinction of still faring fairly well against most anti-archer units. This is because most anti-archer units (such Skirmishers) can survive archer fire due to their pierce armor. But due to the high number of arrows fired the Chu Ko Nu (especially Elite) still deals a considerable amount of damage, especially to Rams. However, they should still try to avoid anti-archer units in general and they match poorly against Huskarls. Most other archers have one more range than Chu Ko Nu and can hit-and-run them.

Chu Ko Nu are best countered with longer ranged archers, Skirmishers, heavy cavalry charges (in large numbers), Huskarls, or siege weapons that deal splash damage.

Further Statistics
As Chu Ko Nu are unique to the Chinese, only technologies that are available to them are shown in the following table:

Civilization Bonuses

 * Chinese: Technologies that benefit Chu Ko Nu are 15%/20% cheaper in the Castle/Imperial Age.

Team Bonuses

 * A team containing Berbers: With Kasbah researched, Chu Ko Nu are created and upgraded 25% faster, and Conscription and Rocketry are researched 25% faster.
 * A team containing Britons: Researching Thumb Ring is 20% faster.
 * A team containing Magyars: Chu Ko Nu have +2 Line of Sight.
 * A team containing Malians: Researching Chemistry and Ballistics is 80% faster.
 * A team containing Saracens: Chu Ko Nu have +1 attack against buildings.
 * A team containing Teutons: Chu Kos Nu are more resistant to conversion.

The Age of Kings

 * Non-Elite Chu Ko Nu train in 19 seconds.

The Conquerors

 * Chu Ko Nu gain a +2 attack bonus against Spearman.
 * Thumb Ring introduced.
 * Chinese: Rocketry introduced.

The Forgotten

 * Non-Elite Chu Ko Nu now train in 16 seconds.

Trivia

 * Chu Ko Nu literally means "The crossbow of Zhuge." Zhuge (also known as Zhuge Liang) was a famous tactician who lived and died during China's Three Kingdoms era. However, the Chinese more commonly refer to it as the "Lian Nu", literally translating to "Repeating Crossbow".
 * Despite its name, the Chu Ko Nu was not invented by Zhuge, being in use some two hundred years before his birth. However, it is likely that he improved its design to make it a more effective weapon of war.
 * The actual Chu Ko Nu had a firing rate of around two arrows per three seconds, making it the most rapid-firing weapon in existence until the invention of the Gatling gun 1800 years later.
 * Due to a quirk in the engine in regards to duplicate projectiles and the design of the arrow projectile, Chu Ko Nu's extra arrows do 0 melee damage along with 3 pierce damage. Normally this makes no difference, but because Rams have -3 melee armor, each duplicated arrow actually deals 3, not 1 damage to Rams. This makes Chu Ko Nu one of the best anti-Ram units in the game as an Elite Chu Ko Nu can deal 16 damage per volley at a distance to Rams.
 * Historically, Chinese military writers considered repeating crossbows to be too weak for battle, but rather was a weapon for home defense against wildlife. Nevertheless, there have been reports of repeating crossbows being used as late as the First Sino-Japanese War in 1894.
 * The Elite upgrade is, in terms of gold, the second most expensive of all unique units (base value), costing 950. Only the Elite War Elephant upgrade costs more gold with 1,200. The Chinese civilization bonus, however, reduces the cost to 760.
 * Even if the target stands right in front of a Chu Ko Nu, the latter can still fail to hit with every arrow in the volley.
 * Elite Chu Ko Nu have a higher Rate of Fire (fire slower) than non-Elite Chu Ko Nu. That makes Chu Ko Nu the only units to actually have a stat downgraded when the unit is upgraded. The reason is the higher number of arrows fired per volley.

History
"The crossbow was invented in China in ancient times and the chu ko nu was an improved crossbow invented there during European Middle Ages. The chu ko nu was something like a semi-automatic crossbow. It was fitted with a magazine of bolts. When the operator pulled back the bowstring, a new bolt was automatically loaded. When the bowstring reached its limit, the weapon fired automatically. The operator pulled back as quickly as he could to maintain a rapid fire. The weaknesses of the weapon were a short range and weaker power compared to larger single-shot crossbows."