Original antique Jian 劍- Chinese double edged steel sword with leather scabbard, Ming dynasty (1368-1644) or earlier. There is a signature in 5-6 Chinese characters in the middle of the blade, which is hard to read. There is another rectangular mark with some illegible characters at the base of the blade, on the same side. Length: 27.25 inches = 69.3 cm; Blade length: 21.75 inches = 55 cm; Leather scabbard length: 20.75 inches = 53 cm; Weight of sword + scabbard: 1128 g = 1 kg 128 g = 2 lb. 7.8 oz. Weight of sword only: 2 lb. 3.2 oz. = 997 g; Weight of scabbard only: 4.6 oz. = 131 g; Steel (iron) blade is attracted to magnet. Ornamented copper handle is heavy, massive and not attracted to magnet; Condition: the blade has some superficial rust, the leather scabbard is cut at the very point. Provenance: private collection of museum curator, St Petersburg, Florida, USA Reference: The jian (Mandarin Chinese: [tɕjɛ̂n], Chinese: 劍, English approximation: /dʒjɛn/ jyehn, Cantonese: [kiːm˧]) is a double-edged straight sword used during the last 2,500 years in China. The first Chinese sources that mention the jian date to the 7th century BCE, during the Spring and Autumn period;[1] one of the earliest specimens being the Sword of Goujian. Historical one-handed versions have blades varying from 45 to 80 centimeters (18 to 31 inches) in length. The weight of an average sword of 70-centimetre (28-inch) blade-length would be in a range of approximately 700 to 900 grams (1.5 to 2 pounds).[2] There are also larger two-handed versions used for training by many styles of Chinese martial arts. Professional jian practitioners are referred to as jianke (Chinese: 劍客; pinyin: jiànkè; lit. 'sword guests' or "swordsmen"; a term dating from the Han dynasty).[3] In Chinese folklore, it is known as "The Gentleman of Weapons" and is considered one of the four major weapons, along with the gun (staff), qiang (spear), and the dao (sabre). These swords are also sometimes referred to as taijijian or "tai chi swords", reflecting their current use as training weapons for tai chi practitioners, though there were no historical jian types created specifically for tai chi.[4] Reference about screw: The screw was one of the last of the simple machines to be invented. It first appeared in Mesopotamia during the Neo-Assyrian period (911-609) BC, and then later appeared in Ancient Egypt and Ancient Greece where it was described by the Greek mathematician Archytas of Tarentum (428–350 BC).