101Leafy researched the games.
Bronze Coin

Mimics the design of ancient currency. The blade can be polished to a high luster.
| Class | Great Sword |
|---|---|
| Rarity | 5 |
| Attack | 864 |
| Defense | +20 |
| Slots | 0 |
| Price | 35,000z |
Upgrades
| Upgraded from | Carbalite Sword |
|---|---|
| Upgrades into | Gaoren Coin |
Can also be made new at the smithy.
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 684.
Materials
Gaoren Pincer ×3, Gaoren Spine ×5, Gaoren Claw ×1, Black Pearl ×20