The YJ-9 (Chinese: 鹰击-9; pinyin: yingji-9; lit. 'Eagle Strike 9') is a Chinese lightweight anti-ship missile manufactured by Hongdu Aviation Industry Corporation. The export version of YJ-9 is called TL-10 (Chinese: 天龙-10; lit. 'Sky Dragon-10') anti-ship missile by Hongdu, or FL-8 (lit. 'Flying Dragon-8') by China National Aero-Technology Import & Export Corporation (CATIC). The missile is also called Kowsar by Iran's Aerospace Industries Organization (AIO).

The TL-10 was unveiled in the 2004 Zhuhai Airshow.

Hongdu Aviation Industry Corporation began the development of TL-10 and TL-6 missiles in the mid-1990s, and conducted test fires in the same period. According to a representative of Hongdu in 2004, the TL-6 and TL-10 programs were purely designed for export, and no missile would be inducted into the People's Liberation Army. Three missile variants were showcased in 2004: the air-to-surface KJ/TL-10B, the surface-to-surface JJ/TL-10A, and the surface-to-surface JJ/TL-6B. TL-6B also had a radar-guided version under development.

The TL-10 and C-701 have similar roles, dimensions, and performance and are both part of Iran's Kowsar program. Jane's Defence Weekly suspected that two companies in China had competing designs intended for Iran's missile program.

TL-10 is specifically designed to engage boats displacing 500 tons or less, and when launched, the missile will first climb to enable the seeker to acquire targets, and then immediately descend down to sea-skimming cruise altitude during its flight. Like the anti-ship version of the C-701, TL-10 is also armed with a television seeker that is interchangeable with TL-6. However, unlike the C-701 guidance has an additional command option which enables the operator to alter the targets, TL-10 is a purely fire-and-forget weapon. Western sources have claimed that the Iranian anti-ship missile Kowsar which is manufactured by the Iran Aviation Industries Organization is based on TL-10 while the Nasr is based on the TL-6.

At the Zhuhai airshow in 2006, the manufacturer revealed the plan already in development to install this missile on various platforms including aircraft, surface ships, and land vehicles. However, like most light anti-ship missiles in the world, it is certain that this missile would not be launched from submarines, as the manufacturer has confirmed. The version that has been successfully completed is the ship-to-ship version, hence the designation JJ/TL-10 at the 6th Zhuhai airshow in 2006, where JJ stands for Jian Jian (舰舰), meaning Ship (to) Ship. Another version developed was KJ/TL-10, the air-launched version, with KJ stands for Kong Jian (空舰), meaning Air (to) ship.

FL-8 (FL = Fei Long / Feilong, or 飞龙 in Chinese, meaning Flying Dragon) is the cheaper coastal defense version of TL-10. Following the tradition of Silkworm missile, a land-based version with the lowest requirement is also developed for this missile: as the missile is stored in a controlled environment in a warehouse on land, the salinity, temperature and relative humidity requirements for the missile itself are greatly reduced. Because it is designed and deployed on land, the associate C4I systems can be located separately: the distributed system prevents electromagnetic interference, and if the C4I system is attacked, the distributed nature of the FL-8 would greatly reduce casualties and damage.

Kowsar (or Kosar) is the Iranian version of TL-10. Noor (missile), the Iranian version of C-802, was previously often widely but erroneously credited by many as the missile that had hit Israeli corvette INS Hanit in the 2006 Lebanon War by Hezbollah, while post incident analysis has suggested that the missiles used was actually much smaller Kowsar instead.