(Records of Military Expeditions), written by Guo Yuansheng, recorded that south-pointing chariots were often stored in the northern gatehouse of the Government Workshops (Shang Fang) of the capital city. However, the later written Song Shu (Book of Song) (6th century) recorded the south-pointing chariot's design and use in further detail, as well as creating the background legend of the device's (supposed) use long before Ma's time, in the Western Zhou dynasty (1050–771 BC). The book also provided a description of the south-pointing chariot's re-invention and use in times after Ma Jun and the Three Kingdoms. The 6th century text, translated by the British scientist and historian Joseph Needham, reads as follows (the south-pointing chariot is referred to as the south-pointing carriage): The last sentence of the passage is of great interest for navigation at sea, since the magnetic compass used for seafaring navigation was not used until the time of Shen Kuo (1031–1095). Although the Song Shu text describes earlier precedents of the south-pointing chariot before the time of Ma Jun, this is not entirely credible, as there are no pre-Han or Han dynasty era texts that describe the device. In fact, the first known source to describe stories of its legendary use during the Zhou period was the Gu Jin Zhu book of Cui Bao (c. 300), written soon after the Three Kingdoms era. Cui Bao also wrote that the intricate details of construction for the device were once written in the Shang Fang Gu Shi (Traditions of the Imperial Workshops), but the book was lost by his time. Japan The invention of the south-pointing chariot also made its way to Japan by the 7th century. The Nihon Shoki (The Chronicles of Japan) of 720 described the earlier Chinese Buddhist monks Zhi Yu and Zhi You constructing several south-pointing Chariots for Emperor Tenji of Japan in 658. This was followed up by several more chariot devices built in 666 as well. Song Shi The south-pointing chariot was also combined with the earlier Han dynasty era invention of the odometer, a mechanical device used to measure distance traveled, and found in all modern automobiles. It was mentioned in the Song dynasty (960–1279) historical text of the Song Shi (compiled in 1345) that the engineers Yan Su (in 1027) and Wu Deren (in 1107) both created south-pointing chariots, which it details as follows. (In Needham's translation, inches and feet (ft) are