As a Malay, the keris is very close and very dear to me. I received my first real keris when I was still a teenager. I began reading up on the keris and sat with elders to learn more about this noble blade. Nonetheless, one statement from my late Guru stuck with me: The keris is just a symbol (Keris ni lambang jaa). It took me some 20 years to explore and discover what he meant by these words.
The keris is made up of three main parts: hulu (hilt), bilah (blade) and sarung (sheath). This relates directly with the concept of zahir (physical) and batin (spiritual) or syariat and hakikat in Islam. The hulu and sarung are the physical aspects (body) of the keris, while the blade is the spiritual aspect (soul) of the keris.
When sheathed, one can only see the hulu and sarung of the keris. The hilt design is very distinct and unique to specific locations and origins. It is basically the identity card of old, and the design and material used for the hulu also reflects the status of the owner. The sampir or cross piece of the sarung is shaped like a ship, reflecting on the maritime nature of the Malay peoples. This "ship" also carries different identities according to various locations of the wearer. A Kedah sampir is different from a Perak one, and a Minang sampir is distinct from one originating in Palembang. Hulu and sarung also have specific designs that are compatible with one another. This combination also carries a specific meaning. The hilt symbolises a man riding on his ship (sampir).
The blade (bilah) is the soul of the keris. As with our soul, it is contained within the body (sarung). In olden days, the blade is hardly shown to the public as it represented the personality (and secrets) of the wearer. It is a very personal and private matter. That is why the blade is always kept hidden unless it is really necessary. The number of lok, type of pamor (if present), length of the blade, presence or absence od certain features, all carry a specific meaning. On a quantum level, these characteristics send out a specific message to the Universe, to God. It is essentially a prayer. Nothing to do with supernatural beings that are sometimes associated with the keris.
What I have written above is just a cursory explanation of the intangible values of the keris. The symbolism is very deep-rooted in Islam and Malay culture. An understanding of sufism could help one to further understand the hidden meanings behind the symbolism of the keris. This is the cultural communication that is an integral part of the Malay civilization. A unique, unwritten language that could only be understood by someone within that culture. This is why "Malay" is based on culture and not just genetics or geaneology.
(This article refers specifically to keris culture other than that of Javanese, Balinese and the like. I am referring to keris identified as "keris Melayu", which includes the tajong and penyalang. Also not included in this discussion are the keris sundang.)