Hi everyone,
IMHO, Tangguh (determining/judging the keris' origin/age) is the hardest exoteric knowledges in keris world. In Java, tangguh usually attributed to a kingdom, in some cases, to a king, or even more, to the empu him/herselves. Some elders in Java thought, Tangguh might means the keris' ages and origin, but also might means the style of certain kingdom which could be copied by other empus (keris makers) from other era. They introduced the term "Toya" (water), which means the water used to temper the blade, to describe the previous style which has been copied to the next era. In fact, for certain tangguh, the younger tangguh might be considered as the perfection of the older style. This could be happened by the "Mutrani" process (to make putra/son, which is, copying the previous invaluable heirlooms) done inside the court.
To determine the tangguh, ones must look very carefully to the overall and details shape of the blade, the materials used, and also the technique employed by the empu to make the blade. Then, ones must also consider the "look/feel" of kerises, known as "Pasikutan" in Java. For instance, the Mataram blades should feel as if you see the handsome young knight, standing tall in front of you, while the Majapahit blades should be "wingit", as if you look at the haunted house
or a holy priest. To feel it, you need no mantras or fasting for days, just look and feel it, just like you look and feel the unfaithful face
Some styles may influence another and mixed, but still there are the differences. One important point the inexperienced students usually forgot, not all kerises' tangguh could be determined, simply because the empu's skill/knowledge was too low, or the lack of materials needed. These unfortunate even usually happened to "empu jawi" (empu outside the court) which made kerises for commoners. Judging such kerises might be very frustating, so some elders in Java introduced one more term : "Tilar Tangguh" (which literally means leaving the tangguh, which is, not comply with any tangguh pattern already known), contrary to "Tangguh Lempoh" (comply with nearly all criteria, if not whole, for certain tangguh).
About the blade in discussion,
I must agree with Alam Shah and others, that it's more likely to be Javanese blade. Bugis' blades tend to be thicker, wider awak-awak but narrower sor-soran, with thicker ganja and bigger ganja's head / sirah cecak.
The thin and slightly curved ganja (sebit lontar) and the pamor on the blade in discussion shows Mataram influences ( c.a. XVII cent. ), but the luks/waves are too shallow for typical Mataram blades. the sogokan are very rough, so for me, it's raised a question, wheter it was made by empu himself or later by the owner/other unskilled smith. The sekar kacang had broken. The crow-beak-shaped sekar kacang very uncommon for 11 luk, and usually reserved for high-rank court official. The dhapur which use beaked-sekar kacang are Pasopati (straight blade), Megantara (7 luk) and Paniwen (7/9 luk ? sorry, I can recall. Got to open the book, too many dhapur for my tiny brain
) and several others. To determine the sekar kacang is original crow beak or broken trunk, just look at the tip of the ganja head and draw the imaginary perpendicular line. The beaked-sekar kacang must nearly touching the line, if not, it might be the elephant trunk which had been broken.
I must admit that the keris knowledge I've learnt was only from Java, especially from the elders in Jogjakarta. Many of the knowledges unwritten, so if you ask me to show the book, I would show you the living book
. Although I've seen some Bali, Bugis and Sumatra blades, I would consider myself inexperience on them. Like Rick said, we are all students here. The more I learn, the more I know that I knew nothing.