シリアル番号
Each Rolex comes with its own unique serial number and can help indicate an approximate production period of the watch. Serial numbers were first introduced in 1926. Rolex serial numbers were issued sequentially, until 1954 when Rolex restarted from #999,999 to #0. Then in 1987 there was an addition of one letter to a 6-digit serial number. Then again in 2010 to the present date Rolex introduced random serial numbers.