The Iron Flail is one of the most important heavy cavalry units offered by the Chinese; depending on the situation, if used with Beiyang Army (Keshiks + Steppe Riders) units, the Forbidden Army proves good against artillery, light cavalry, light infantry, Skirmishers, and archers. When used with the Imperial Army, they are good against heavy infantry, heavy cavalry, archers, skirmishers and light infantry; for heavy artillery have lesser impact. However, they are most effective when combined with either Hand Mortars or/and Flying Crows and with Territorial Army or Old Han Army units.
The flail is a medieval weapon used primarily in Europe during the thirteenth to fifteenth centuries. Its construction consists of a weighted head, often spiked, that is attached to a wooden handle with a whip or length of chain. While not as commonly used in Asia, the flail was quite similar to other flail weapons, such as the Chinese nunchaku, or two-section staff, and Sanjiegun, or three-section staff.