Offering a knife is a practice laden with symbols of power and honor, found among the Vikings as representing trust, and among the Japanese as a symbol of honor. However, this offering can also be seen as evil without the counter-gift of a coin.
The coin, which can be a collector’s item or a historic franc, acts as a symbolic regulator that “buys” the knife and neutralizes the negative implications of this gift, thus preserving the values of honor and mutual respect.