What Is Eohan?

What is Eohan?

Eohan is a hypertext dictionary giving the historical pronunciations of about 26,000 Chinese characters like the one below (拍 pāi, 'to pat with the hand'), together with the data from which those historical pronunciations can be reconstructed. The red box contains the modern pronunciation in various languages, the green box contains other useful information and the blue box contains the historical pronunciations and links to the ancient texts from which they can be deduced.

Dialects Sinoxenic
Mandarin
pāi
Japanese
haku
hyou
Korean
pak
Cantonese
paak3
Vietnamese
phếch
Graphical Phonetic
Radical 64.5 Karlgren
685
Four Corner Code 5600.0 Wieger
143
Pulleyblank Baxter Karlgren Sources
Early Mandarin
p‘ajˇ
Zhongyuan
Yinyun
Late Middle Chinese
p‘aajk
Yunjing
Early Middle Chinese
p‘ark
phæk
p‘ak
Guangyun
Old Chinese
[p‑pr]ák
[phr]ak
p‘ak1
Shijing
GSR

In the blue box, the link to the Middle Chinese pronouncing dictionary Guangyun leads to the information that the character 拍 is listed in book 5, tone 4, section 20, subsection 192: homophone 3592:

The link to the Middle Chinese rhyme book Yunjing leads to the information that it occurs in rhyme table 33 (waizhuan, kaihe) with initial 2, grade 2 and tone 4:

外轉笫三十三開

𣑭
𪐏

The great Swedish linguist Bernhard Karlgren first made sense of this enigmatic method of specifying pronuncation and saw how to use it to reconstruct the sounds which it is meant to indicate (p‘ak in his system of phonetic transcription). His work has been continued and refined by, among others, Edwin Pulleyblank and William Baxter. Given that the puzzle has been solved, anyone can turn their reasoning into software and generate the Middle Chinese pronunciation of each character listed in Guangyun and Yunjing. Their reconstructions of other periods of Chinese can be reproduced on similar lines.

That is what I have done in writing Eohan. 35 Python scripts take texts including Guangyun and Yunjing as input, generate historical Chinese and write it to a database. A separate bundle of software creates the website. A PHP app embedded in Wordpress generates a page of Eohan by making a remote procedure call to an SQL query on multiple tables of the database and returning the result wrapped in HTML and CSS.