Santoku means the three virtues in Japanese, we're not too sure which three virtues they are but it has named the Japanese knife which has three abilities; slicing, dicing and mincing.
If we relate it to the sword of the East, the claidheamh soluis or sword of light of which the original would be Nuada's sword crafted in the mythical city of Findias. It has 3 powers; the sword glowed with the light of the sun, thus blinding opponents, was irresistible in battle like a raging sea and had the power to cut his enemies in half. Here we see the triumvirate of light or air, water as the irresistible force and earth in the cleaving. We see similar epithets for Excalibur in the Arthurian cycle.
As an aside, for me, this places Findias as a city in the East, whilst Gorias (source of Lugh's lance) is in the south, the Dagda's cauldron from Murias in the West and finally the stone of destiny from Falias in the North.
In cycling the three virtues are Mind, Body and Machine and is what inspired this post. For me, Gewessi has these 3 virtues, that are possessing an earth based philosophy (Òran Mór), a spirituality (Irmunsûl) that enhances your life and applying logic to your world view (Logos).
Three Druidic Triads
Three blessed virtues of the noble: being good in serving others, having a good temperament, and keeping secrets.
The three virtues of a Bard are to tell the truth, seek justice for the oppressed, and exercise reason in difficult situations.
The Awen symbolizes in man the three virtues: courage, brotherhood, and selfless service.
The three virtues of - Li: Propriety, Chih - Wisdom, Jen - human heartedness
The first character, li, occupies an august, noble position in East Asian thought. Something can be discovered about the fundamental meaning of the character by examining its component parts. If one passes a vertical line through the middle of the character, two distinct segments, shih1 and li, appear. The left-hand side (here shih, `spirit' or`ghost') imparts meaning and is called the `signific' or `radical.' So here we have a word pronounced li having something to do with spirits - in this case, sacrifices to spirits or the ceremonies and proper rules associated with those sacrifices.
The second character of the three virtues, chih (wisdom), is as difficult of interpretation as it is of practice. In contemporary usage it means `wisdom,' `intelligence.' The compound chih-hui, means I.Q. and chih-li means `intellectual power.' The phonetic portion of chih is chih. In ancient times the two characters were used interchangeably to mean `wisdom' or `knowledge.' There is, however, once again an inherent ethical force in the classical usage.
The third virtue, jen, has nearly as rich a philosophical interpretation as li. Ideographically, the left hand signific represents a man; the right is the character erh meaning `two.' It is not a phonetic. It represents man and his moral relation to others. The great nineteenth century Scottish sinologue James Legge always rendered jen as `benevolence.' In contemporary Chinese the compound ren-ai is very common and is most usually rendered as `love' (Greek agape). Many contemporary scholars use the word `human-heartedness' as an equivalent. Compassion, goodwill, humanity, kindness, mercy are all close.
From this website about the game Go