Found another book by the same author of "SOME MEDIEVAL REPRESENTATIONS OF SINHALA WRESTLERS AND GLADIATORS (1937) by P E P Deraniyagala", cept this book is titled "Sinhala Weapons and Armor". He was the director of museums in Ceylon.....
A quote from this book,"The hilt of the sword should have a pommel of lotus petals; the middle part should be decorated and possess auspicious figures as of lions,etc. A circle at the middle of a weapon is inauspicious".
This puts a most intrigueing twist as bad, ill,misfortune,unfavorable are synonems for inauspicious.
The entire book is posted at this site and is fascinating reading: