一揮掃蕩 血染山河
I'm not sure what hidden meaning this phrase contains, but a literal translation would be "With one swing, blood stain hills and rivers" somewhere along those line. I'm guessing its a Chinese idiom from war times or something. Hope this helps.
Source: Myself, I can read Chinese
Yup.
"one sweep stains the mountains and rivers in blood"
The Mod Story
Now, I found a reference to that being engraved on one of Admiral Yi Sun Shin's sword, but I can not verify, however it makes
sense.
"The compound is dedicated to Adm. Yi Sun-shin, perhaps Korea’s most revered war hero. Adm. Yi Sun-shin is reputed to have fought off Japanese invaders with the aid of two huge swords (77 inches long, 12 pounds). They — along with two Chinese swords presented by the Chinese emperor, spears, fire arrows and even a scale model of a so-called turtle ship (the world’s first iron-clad vessel, developed by Adm. Yi Sun-shin) — are permanently displayed in the shrine’s Relics Museum.
Both of Adm. Yi Sun-shin’s swords can be viewed up close in a brightly lit glass case. Nearby photographs reveal the hanja (Chinese-style writing) that is engraved on the tang, that part of the blade normally hidden by the handle. A plaque lists the swords’ specifications and history.
A number of theories exist in South Korea to explain how a mere mortal could have used such massive weapons. Some fancifully argue that Koreans grew larger then (some 400 years ago) and that wielding a 12-pound sword would have been possible. Others say the swords were never intended for use in battle but were symbols, similar to flags and standards, around which troops rallied."
Ancient Korean Swords and Sword Arts (Part 1) – - Black Belt