Blacksmiths (鍛冶屋, Kajiya) are a recurring gameplay mechanic in the Suikoden series. They are the primary means of weapon upgrades throughout the series.
Blacksmiths, for a fee, will sharpen the weapons of your party members, increasing their attack prowess. Each blacksmith has a certain limit to how much they can improve a level, necessitating either a visit for a better blacksmith or giving the blacksmith a hammer which allows them to raise their limit.
- Genso Suikoden Kiwami Encyclopedia, page 35