What is "pyeonjeon"

Pyeonjeon, or aegisal (baby arrow) is a small archery bolt, fired from within a longer bamboo shaft, allowing the use of a full sized bow to propel a short bolt. A unique creation in the Korean archery, this weapon was considered a national secret during the Japanese invasions of Korea (1592-1598). The pyeonjeon made it impossible for the enemy to reuse the arrow, and also allowed Koreans to easily double or triple the number of their arrows in a siege scenario if the arrow supplies were running low. Its traditional range is 350 meters, five times the effective range of Arquebus or Tanegashima. Further more, the short bolts had longer range and flatter trajectory with a faster velocity and penetrating power.