This practice changed in 2021 when gold was used for the first time for a coin celebrating 150 years of Japan's modern currency system.
For the Osaka Garden Exposition, coins were minted that feature a right facing bust of the goddess Flora with flowers in her hair on the obverse.
[4] Only one commemorative coin was struck in 1993 which celebrates the wedding of then Crown Prince of Japan Naruhito to then princess Masako.
[5][6] The design chosen for the 5000 yen coin depicts a pair of cranes in flight on the obverse, while the reverse has the Imperial Crest.
[1] 5000 yen commemorative coins were minted again in sterling silver to celebrate the 1998 Winter Olympics, which were held in the Japanese city of Nagano.
In terms of added value, its debated within the numismatic community if breaking up modern proof sets to grade individual coins is a worthwhile investment or not.