This appears to be a lead 100 mon from the Japanese district of Hosokura, catalogs list the date as circa 1863. This would be a very large and heavy coin.
This particular one is missing a proof mark, but that is not uncommon with these coins.
A genuine example in this condition would run close to $1,000 as they are quite rare.
Cannot tell if it's authentic from the photos alone, but the details and surface seems about right compared to several other examples on the net.