The mon were heraldic crests of symbols worn by the samurai on their clothing. These crests served as identification marks, by showing to which clan or family the samurai belonged. It was a common practice in times of war to fasten a sashimono (banner) to the warrior's armor, displaying their mon. The mon originally had simple designs of shapes taken from nature or geometric patterns, but the meaning behind these designs were not simple and gave each mon great social, moral and ethical significance. It was an honor to wear one, but also a responsibility. The mon was a sign of a samurai's lord, or the clan, and had to be respected. The book Budo Shoshinshu by Yuzan Daidoji gives in great detail information about the proper ways to wear the mon according to the dress code.

Today, the meaning of mon have not truly changed, since they still represent the family's honor. A true Budoka recognizes that and won't diminish its significance. In a world concerned with clothing labels and trademarks that show the quality of what we wear, the mon becomes a trademark of a higher level, that of the spirit. It was written of the mon, "Thus, desecrating the lord's family crest, and one will lose divine favor, and unawares, incur the master's punishment."

As with the sword, the mon defines itself in its bearer's attitude. Owning one means nothing, unless you understand its significance and shape your life and attitude accordingly.