A jig is a tool of woodwork, ironwork, fitter, machinery, electric control, and other handicrafts. It is mainly used as a tool to assist in controlling position or movement (or both).　　 The terms 'fixture' and 'fixture' are often confused and even misused because of their similar uses.　　 Fixture focuses on working and guiding tools; fixture focuses on holding tools in a fixed position. Some devices that have both of these functions (control and guidance tools) are also called fixtures, but devices that only hold but do not have a guidance tool are called 'fixtures' rather than 'fixtures.' After entering the era of numerical control systems, the use of jigs has been reduced.