Bitter melon/cucumber seed 's ovel/elipse shape (bottom-right of the first pic).
The name 's interchangable with the turtle mark.
The mark was used by both LumPang and Aranyik guilds.
The round mark is called Dok Keaw (Orange Jessamine, flower). It 's not found in Aranyik 's product. Mostly related with LumPang guild.
Currently, there are hypothesis for marks on the spine. The first one is helping a calculation or strategy note. Another one which 's come from more reliable source is that spine marks are blade registration. The marks can be transfer to a paper or cloth with a piece of charcoal and a copy will be kept by town/city officer.
The slug, however, is related with spiritual believe. The most reliable one is that the copper material has a warding power against evil or person's spiritual protection. Some smiths point out the metal keep rust away. But the hypothesis 's less solid sice it 's scientificly not true.
Both marks and slugs may serve their purpose in the old time. But in this modern time, although the marks and slugs are traditional preserved, but its real purpose has been forgotten and they are purely used as a decoration.
