Sakai is home to the Tomb of Emperor Nintoku, which is registered as a World Heritage Site. The mausoleums of Emperor Hanzei, Emperor Richu, and Emperor Nintoku, are called Mimihara three mausoleums. These have been important to me since I was a child. I used to call the burial mounds “Goryo-san”. 
“Mausoleum of Emperor Nintoku” includes kanji “徳<TOKU>” meaning “acquired character”, “socially valuables qualities”, and “desired attitude that widely affects others” means.

After considering these Kanji “徳<TOKU>”, they would be a good character to let people around the world know about Sakai knives and use them.