This is a tin coin from Johore Sultanate era. This type of coin is called cash or katun. It is undated but probably from the 18th Century based on the classification made by Major Fred Pridmore.In Saran Singh's this is classified as Group D-Octogonal-class IIX.
The coin in question here is more round or probably the octagonal edges all were worn out leaving it almost round shape. However I suspected this coin is round when it was made based on the dots which rim the coin in circle instead of in octagon
Johor is located in the southern tip of Peninsular of Malaysia as well as the most southern point of the Asian Continent. The name of Johor originated from the Arabic word Jawhar which means jewel. It is also known by its Arabic honorific, Darul Takzim ( Abode of Dignity). The Sultanate of Johor was founded by Sultan Alauddin Riayat Shah II , the son of exiled last Sultan of Malacca ( Sultan Mahmud Shah) in 1528 CE. Johor was part of Malaccan Sultanate prior to Malacca occupation by Portuguese in 1511 CE.
Obv: Khalifah Sultan Shah
Weight : 1.25 gm
Dim : 17mm
Rarity : Very Rare ( if it is deemed to have a round shape)
Ref : SS38