(i) The double tsheg
In standard Tibetan orthography from the 10th century onwards each syllable is separated by single dot (tsheg), level with the tops of the main letters. In the early inscriptions, a double dot (much like the colon) is often used instead. The double tsheg seems to have gradually fallen from use in the early 9th century. It appears quite consistently in the two major 8th century inscriptions, the Zhöl and Samye pillars, but when we get to the early 9th century pillars its role is reduced to marking the ends of lines and as a decorative mark between two shad.
The double tsheg appears in a number of Dunhuang manuscripts. It is found in the Old Tibetan Annals and other historical texts, and also commonly appears in some legal and divination texts.
In his recent study of one of the legal documents (IOL Tib J 740), Brandon Dotson tabulated the occurence of the double tsheg after different final syllables. He found that the single tsheg was used about 75% of the time after a final nga, na, da and ra but on 5% of the time after other endings (where the double tsheg was used instead).
As Dotson points out, this is probably just because it is more difficult to write the double tsheg after nga, na, da and ra because the lower parts of those letters are more likely to get in the way of the lower dot. Dotson also sees this pattern (though with less regularity) in the old pillar inscriptions that use the double tsheg, such as the Zhöl pillar.
The double tsheg appears rather sporadically at the end of some lines in the 805/6 Temple of the Hat inscription, but is absent in the 812 inscription at the same site. This suggests that its use was discouraged as part of the revisions of the written language introduced by Senaleg in 812. The double tsheg is not used with any regularity in other inscriptions after this date. We also do not find it in any of the Dunhuang manuscripts that have been dated to the post-imperial period (i.e. after the mid-9th century). Therefore the double tsheg may turn out to be very useful for dating the Dunhuang manuscripts—keeping in mind of course that copyists are quite capable of reproducing an obsolete form of punctuation in later manuscripts.
(ii) The mid-line tsheg
A tsheg which sits in the middle of the vertical space occupied by each letter, rather than at the top, is also found in the pillar inscriptions and the Dunhuang manuscripts. It can be seen alongside the double tsheg in the Karchung pillar inscription pictured above. It is also found as the dominant form of the tsheg in some manuscripts, such as the fragment of the Prātimokṣa sūtra pictured here.
The advantage of the mid-line tsheg to the scribe can be seen in this manuscript example. It allows the letters to be written closer to each other, especially with letters like nga, ta and da, where the tsheg fits snugly into the open right side of the letter.
Although it is my impression that the mid-line tsheg does not occur in the later (i.e. 10th century) Dunhuang manuscripts, this is a hypothesis yet to be proven.
(iii) The long tsheg
In many manuscripts the tsheg is lengthened into a line, something between the usual tsheg and the shad. This long tsheg is not usually used with any regularity, and I suspect it is a scribal quirk. It may have originated from a double tsheg written without a pen lift.
Once again it is my impression that the long tsheg does not occur in the later (i.e. 10th century) Dunhuang manuscripts, but this hypothesis is yet to be proven.
1. Dotson, Brandon. 2007. “Divination and Law in the Tibetan Empire: The Role of Dice in the Legislation of Loans, Interest, Marital Law and Troop Conscription”, in M. Kapstein and B. Dotson (eds.), Contributions to the Cultural History of Early Tibet. Leiden: Brill. 3–77.
2. de la Vallée Poussin, Louis. 1962. Catalogue of the Tibetan Manuscripts From Tun-Huang in the India Office Library. Oxford: Oxford University Press.
1. Detail from Hugh Richardson’s photograph of the Karchung pillar. This images is © the Pitt Rivers Museum, Oxford. See their website: The Tibet Album.