It is Shi Bao's cloak knife. In the "Water Margin" behind the battle against Fang La, there were two very special ? equipment? One thing Wood Yan Guang's triple armor, the book introduced when said that this armor knife cut impervious, axe can not be broken, the whole set of armor is divided into three layers, the outermost layer is a metal plate, the middle layer is a tough animal skin, and the innermost layer of locks armor. Such a piece of armor is really difficult to break open its defense, this three layer defense any layer is the use of extremely rare materials, separate take out of the production of armor is a treasure, so the Wood Yan light of this triple armor belongs to the "Water Margin" in the defense of the most powerful piece of equipment.
But I don't know whether Shi Naiyan deliberately set up, after the introduction of this? No spear can pierce the shield? then introduced Shi Bao's cloak sword. The introduction of the cloak knife is not as detailed as the triple armor, but only one of them is enough, one of which says that this knife can cleave through all the triple armor. It was obvious that the cloak sword was specially designed by Shi Naian to target triple armor. Though Shi Bao and Wu Yan Guang were not in opposing camps, and designing it that way was likely just a bit of fun.
Whether the design of the cloak sword is serious or fun, at least in the Water Margin, it is the only weapon that can cut through the triple armor of Wu Yan Guang. So Shi Bao's cloak sword is the most powerful weapon in Water Margin. But even the most powerful weapon also depends on the strength of the master who uses it, otherwise it can only be a pearl in the dust. Shi Bao finally died in battle, and the cloak sword lost its luster.
If you want to combine the strength of the weapon holder, then undoubtedly Lu Junyi's golden spear is the most powerful. Because Lu Junyi was initially very rich and was known to be a landlord fighter, he certainly didn't value money when building his weapon, so the material of the Golden Spear was made using the cherished extraterrestrial meteorite iron under the sky. Plus Lu Junyi's unrivaled combat power, then the combination is the Golden Spear is the most powerful.
In summary, if purely on the weapon, then the cloak sword is the most powerful, if combined with the use of the weapon's owner, then the golden spear is the most powerful.