Siddhaṃ script
Siddhaṃ (also Siddhāṃ[7]), also known in its later evolved form as Siddhamātṛkā,[8] is a medieval Brahmic abugida, derived from the Gupta script and ancestral to the Nāgarī, Assamese, Bengali, Tirhuta, Odia and Nepalese scripts.[9]
| Siddham script Siddhaṃ 𑖭𑖰𑖟𑖿𑖠𑖽 | |
|---|---|
|  The word Siddhaṃ in Siddhaṃ script | |
| Script type | |
| Time period | c. late 6th century[1] – c. 1200 CE[note 1] | 
| Direction | left-to-right  | 
| Languages | Sanskrit | 
| Related scripts | |
| Parent systems | |
| Child systems | |
| Sister systems | Sharada,[2][3][5] Tibetan,[4] Kalinga, Bhaiksuki | 
| ISO 15924 | |
| ISO 15924 | Sidd (302), Siddham, Siddhaṃ, Siddhamātṛkā | 
| Unicode | |
| Unicode alias | Siddham | 
| U+11580–U+115FF Final Accepted Script Proposal | |
| 
 | |
| Brahmic scripts | 
|---|
| The Brahmic script and its descendants | 
The word Siddhaṃ means "accomplished" or "perfected" in Sanskrit. The script received its name from the practice of writing Siddhaṃ, or Siddhaṃ astu (may there be perfection), at the head of documents. Other names for the script include bonji (Japanese: 梵字) lit. "Brahma's characters" and "Sanskrit script" and Chinese: 悉曇文字; pinyin: Xītán wénzi lit. "Siddhaṃ script".
History
    

The Siddham script evolved from the Gupta Brahmi script in the late 6th century CE.[1]
Many Buddhist texts taken to China along the Silk Road were written using a version of the Siddhaṃ script. This continued to evolve, and minor variations are seen across time, and in different regions. Importantly, it was used for transmitting the Buddhist tantra texts. At the time it was considered important to preserve the pronunciation of mantras, and Chinese was not suitable for writing the sounds of Sanskrit. This led to the retention of the Siddhaṃ script in East Asia. The practice of writing using Siddhaṃ survived in East Asia where Tantric Buddhism persisted.
Kūkai introduced the Siddhaṃ script to Japan when he returned from China in 806, where he studied Sanskrit with Nalanda-trained monks including one known as Prajñā (Chinese: 般若三藏; pinyin: Bōrě Sāncáng; 734–c. 810). By the time Kūkai learned this script, the trading and pilgrimage routes over land to India had been closed by the expanding Abbasid Caliphate.[10]
In the middle of the 9th century, China experienced a series of purges of "foreign religions", thus cutting Japan off from the sources of Siddhaṃ texts. In time, other scripts, particularly Devanagari, replaced Siddhaṃ in India, while Siddhaṃ's northeastern derivative called Gaudi evolved to become the Assamese, Bengali, Tirhuta, Odia and also the Nepalese scripts in the eastern and northeastern regions of South Asia,[11][12] leaving East Asia as the only region where Siddhaṃ is still used.
There were special forms of Siddhaṃ used in Korea that varied significantly from those used in China and Japan, and there is evidence that Siddhaṃ was written in Central Asia, as well, by the early 7th century.
As was done with Chinese characters, Japanese Buddhist scholars sometimes created multiple characters with the same phonological value to add meaning to Siddhaṃ characters. This practice, in effect, represents a 'blend' of the Chinese style of writing and the Indian style of writing and allows Sanskrit texts in Siddhaṃ to be differentially interpreted as they are read, as was done with Chinese characters that the Japanese had adopted. This led to multiple variants of the same characters.[13]
Characteristics
    
Siddhaṃ is an abugida rather than an alphabet, as each character indicates a syllable, including a consonant and (possibly) a vowel. If the vowel sound is not explicitly indicated, the short 'a' is assumed. Diacritic marks are used to indicate other vowels, as well as the anusvara and visarga. A virama can be used to indicate that the consonant letter stands alone with no vowel, which sometimes happens at the end of Sanskrit words.
Siddhaṃ texts were usually written from left to right then top to bottom, as with other Brahmic scripts, but occasionally they were written in the traditional Chinese style, from top to bottom then right to left. Bilingual Siddhaṃ-Japanese texts show the manuscript turned 90 degrees clockwise and the Japanese is written from top to bottom, as is typical of Japanese, and then the manuscript is turned back again, and the Siddhaṃ writing is continued from left to right (the resulting Japanese characters appear sideways).
Over time, additional markings were developed, including punctuation marks, head marks, repetition marks, end marks, special ligatures to combine conjuncts and rarely to combine syllables, and several ornaments of the scribe's choice, which are not currently encoded. The nuqta is also used in some modern Siddhaṃ texts.
Vowels
    
- Independent form - Romanized - As diacritic with  - Independent form - Romanized - As diacritic with  - 𑖀  - a - 𑖎𑖿𑖧  - 𑖁  - ā - 𑖎𑖿𑖧𑖯  - 𑖂  - i - 𑖎𑖿𑖧𑖰  - 𑖃  - ī - 𑖎𑖿𑖧𑖱  - 𑖄  - u - 𑖎𑖿𑖧𑖲  - 𑖅  - ū - 𑖎𑖿𑖧𑖳  - 𑖊  - e - 𑖎𑖿𑖧𑖸  - 𑖋  - ai - 𑖎𑖿𑖧𑖹  - 𑖌  - o - 𑖎𑖿𑖧𑖺  - 𑖍  - au - 𑖎𑖿𑖧𑖻  - 𑖀𑖽  - aṃ - 𑖎𑖿𑖧𑖽  - 𑖀𑖾  - aḥ - 𑖎𑖿𑖧𑖾  
- Alternative forms  ā ā i i i i ī ī ī ī u u ū ū o o au au aṃ aṃ
- Independent form - Romanized - As diacritic with  - Independent form - Romanized - As diacritic with  - 𑖆  - ṛ - 𑖎𑖴  - 𑖇  - ṝ - 𑖈  - ḷ - 𑖉  - ḹ 
Consonants
    
- Stop - Approximant - Fricative - Tenuis - Aspirated - Voiced - Breathy voiced - Nasal - Glottal - 𑖮  h h- Velar - 𑖎  k k- 𑖏  kh kh- 𑖐  g g- 𑖑  gh gh- 𑖒  ṅ ṅ- Palatal - 𑖓  c c- 𑖔  ch ch- 𑖕  j j- 𑖖  jh jh- 𑖗  ñ ñ- 𑖧  y y- 𑖫  ś ś- Retroflex - 𑖘  ṭ ṭ- 𑖙  ṭh ṭh- 𑖚  ḍ ḍ- 𑖛  ḍh ḍh- 𑖜  ṇ ṇ- 𑖨  r r- 𑖬  ṣ ṣ- Dental - 𑖝  t t- 𑖞  th th- 𑖟  d d- 𑖠  dh dh- 𑖡  n n- 𑖩  l l- 𑖭  s s- Bilabial - 𑖢  p p- 𑖣  ph ph- 𑖤  b b- 𑖥  bh bh- 𑖦  m m- Labiodental - 𑖪  v v
- Conjuncts in alphabet - 𑖎𑖿𑖬  kṣ kṣ- 𑖩𑖿𑖩𑖽  llaṃ llaṃ
- Alternative forms  ch ch j j ñ ñ ṭ ṭ ṭh ṭh ḍh ḍh ḍh ḍh ṇ ṇ ṇ ṇ th th th th dh dh n n m m ś ś ś ś v v
Conjuncts
    
- kkṣ - -ya - -ra - -la - -va - -ma - -na - 𑖎  k k- 𑖎𑖿𑖧  kya kya- 𑖎𑖿𑖨  kra kra- 𑖎𑖿𑖩  kla kla- 𑖎𑖿𑖪  kva kva- 𑖎𑖿𑖦  kma kma- 𑖎𑖿𑖡  kna kna- 𑖨𑖿𑖎  rk rk- 𑖨𑖿𑖎𑖿𑖧  rkya rkya- 𑖨𑖿𑖎𑖿𑖨  rkra rkra- 𑖨𑖿𑖎𑖿𑖩  rkla rkla- 𑖨𑖿𑖎𑖿𑖪  rkva rkva- 𑖨𑖿𑖎𑖿𑖦  rkma rkma- 𑖨𑖿𑖎𑖿𑖡  rkna rkna- 𑖏  kh kh- total 68 rows. 
- ↑ The combinations that contain adjoining duplicate letters should be deleted in this table.
- 𑖒𑖿𑖎  ṅka ṅka- 𑖒𑖿𑖏  ṅkha ṅkha- 𑖒𑖿𑖐  ṅga ṅga- 𑖒𑖿𑖑  ṅgha ṅgha- 𑖗𑖿𑖓  ñca ñca- 𑖗𑖿𑖔  ñcha ñcha- 𑖗𑖿𑖕  ñja ñja- 𑖗𑖿𑖖  ñjha ñjha- 𑖜𑖿𑖘  ṇṭa ṇṭa- 𑖜𑖿𑖙  ṇṭha ṇṭha- 𑖜𑖿𑖚  ṇḍa ṇḍa- 𑖜𑖿𑖛  ṇḍha ṇḍha- 𑖡𑖿𑖝  nta nta- 𑖡𑖿𑖞  ntha ntha- 𑖡𑖿𑖟  nda nda- 𑖡𑖿𑖠  ndha ndha- 𑖦𑖿𑖢  mpa mpa- 𑖦𑖿𑖣  mpha mpha- 𑖦𑖿𑖤  mba mba- 𑖦𑖿𑖥  mbha mbha
- 𑖒𑖿𑖧  ṅya ṅya- 𑖒𑖿𑖨  ṅra ṅra- 𑖒𑖿𑖩  ṅla ṅla- 𑖒𑖿𑖪  ṅva ṅva- 𑖒𑖿𑖫  ṅśa ṅśa- 𑖒𑖿𑖬  ṅṣa ṅṣa- 𑖒𑖿𑖭  ṅsa ṅsa- 𑖒𑖿𑖮  ṅha ṅha- 𑖒𑖿𑖎𑖿𑖬  ṅkṣa ṅkṣa
- 𑖭𑖿𑖎  ska ska- 𑖭𑖿𑖏  skha skha- 𑖟𑖿𑖐  dga dga- 𑖟𑖿𑖑  dgha dgha- 𑖒𑖿𑖎𑖿𑖝𑖿𑖨  ṅktra ṅktra- 𑖪𑖿𑖓  vca/bca vca/bca- 𑖪𑖿𑖔  vcha/bcha vcha/bcha- 𑖪𑖿𑖕  vja/bja vja/bja- 𑖪𑖿𑖖  vjha/bjha vjha/bjha- 𑖕𑖿𑖗  jña jña- 𑖬𑖿𑖘  ṣṭa ṣṭa- 𑖬𑖿𑖙  ṣṭha ṣṭha- 𑖟𑖿𑖚  dḍa dḍa- 𑖟𑖿𑖛  dḍha dḍha- 𑖬𑖿𑖜  ṣṇa ṣṇa- 𑖭𑖿𑖝  sta sta- 𑖭𑖿𑖞  stha stha- 𑖪𑖿𑖟  vda/bda vda/bda- 𑖪𑖿𑖠  vdha/bdha vdha/bdha- 𑖨𑖿𑖝𑖿𑖭𑖿𑖡  rtsna rtsna- 𑖭𑖿𑖢  spa spa- 𑖭𑖿𑖣  spha spha- 𑖟𑖿𑖤  dba dba- 𑖟𑖿𑖥  dbha dbha- 𑖨𑖿𑖎𑖿𑖬𑖿𑖦  rkṣma rkṣma
- 𑖨𑖿𑖎𑖿𑖬𑖿𑖪𑖿𑖧  rkṣvya rkṣvya- 𑖨𑖿𑖎𑖿𑖬𑖿𑖪𑖿𑖨𑖿𑖧  rkṣvrya rkṣvrya- 𑖩𑖿𑖝  lta lta- 𑖝𑖿𑖎𑖿𑖪  tkva tkva- 𑖘𑖿𑖫  ṭśa ṭśa- 𑖘𑖿𑖬  ṭṣa ṭṣa- 𑖭𑖿𑖮  sha sha- 𑖤𑖿𑖎𑖿𑖬  bkṣa bkṣa
- 𑖢𑖿𑖝  pta pta- 𑖘𑖿𑖎  ṭka ṭka- 𑖟𑖿𑖭𑖿𑖪  dsva dsva- 𑖘𑖿𑖬𑖿𑖔𑖿𑖨  ṭṣchra ṭṣchra
- 𑖕𑖿𑖕  jja jja- 𑖘𑖿𑖘  ṭṭa ṭṭa- 𑖜𑖿𑖜  ṇṇa ṇṇa- 𑖝𑖿𑖝  tta tta- 𑖡𑖿𑖡  nna nna- 𑖦𑖿𑖦  mma mma- 𑖩𑖿𑖩  lla lla- 𑖪𑖿𑖪  vva vva
- Alternative forms of conjuncts that contain ṇ.
- 𑖜𑖿𑖘  ṇṭa ṇṭa- 𑖜𑖿𑖙  ṇṭha ṇṭha- 𑖜𑖿𑖚  ṇḍa ṇḍa- 𑖜𑖿𑖛  ṇḍha ṇḍha
ṛ syllables
    
- 𑖎𑖴  kṛ kṛ- 𑖏𑖴  khṛ khṛ- 𑖐𑖴  gṛ gṛ- 𑖑𑖴  ghṛ ghṛ- 𑖒𑖴  ṅṛ ṅṛ- 𑖓𑖴  cṛ cṛ- 𑖔𑖴  chṛ chṛ- 𑖕𑖴  jṛ jṛ- 𑖖𑖴  jhṛ jhṛ- 𑖗𑖴  ñṛ ñṛ
Some sample syllables
    
- 𑖨𑖿𑖎  rka rka- 𑖨𑖿𑖎𑖯  rkā rkā- 𑖨𑖿𑖎𑖰  rki rki- 𑖨𑖿𑖎𑖱  rkī rkī- 𑖨𑖿𑖎𑖲  rku rku- 𑖨𑖿𑖎𑖳  rkū rkū- 𑖨𑖿𑖎𑖸  rke rke- 𑖨𑖿𑖎𑖹  rkai rkai- 𑖨𑖿𑖎𑖺  rko rko- 𑖨𑖿𑖎𑖻  rkau rkau- 𑖨𑖿𑖎𑖽  rkaṃ rkaṃ- 𑖨𑖿𑖎𑖾  rkaḥ rkaḥ- 𑖒𑖿𑖎  ṅka ṅka- 𑖒𑖿𑖎𑖯  ṅkā ṅkā- 𑖒𑖿𑖎𑖰  ṅki ṅki- 𑖒𑖿𑖎𑖱  ṅkī ṅkī- 𑖒𑖿𑖎𑖲  ṅku ṅku- 𑖒𑖿𑖎𑖳  ṅkū ṅkū- 𑖒𑖿𑖎𑖸  ṅke ṅke- 𑖒𑖿𑖎𑖹  ṅkai ṅkai- 𑖒𑖿𑖎𑖺  ṅko ṅko- 𑖒𑖿𑖎𑖻  ṅkau ṅkau- 𑖒𑖿𑖎𑖽  ṅkaṃ ṅkaṃ- 𑖒𑖿𑖎𑖾  ṅkaḥ ṅkaḥ
Usage
    
In Japan, the writing of mantras and copying/reading of sutras using the Siddhaṃ script is still practiced in the esoteric schools of Shingon Buddhism and Tendai as well as in the syncretic sect of Shugendō. The characters are known as shittan (悉曇) or bonji (梵字, Chinese: Fànzì). The Taishō Tripiṭaka version of the Chinese Buddhist canon preserves the Siddhaṃ characters for most mantras, and Korean Buddhists still write bījas in a modified form of Siddhaṃ. A recent innovation is the writing of Japanese language slogans on T-shirts using Bonji. Japanese Siddhaṃ has evolved from the original script used to write sūtras and is now somewhat different from the ancient script.[14][15][16]
It is typical to see Siddhaṃ written with a brush, as with Chinese writing; it is also written with a bamboo pen. In Japan, a special brush called a bokuhitsu (朴筆, Cantonese: pokbat) is used for formal Siddhaṃ calligraphy. The informal style is known as "fude" (筆, Cantonese: "moubat").
Siddhaṃ fonts
    
Siddhaṃ is still largely a hand written script. Some efforts have been made to create computer fonts, though to date none of these are capable of reproducing all of the Siddhaṃ conjunct consonants. Notably, the Chinese Buddhist Electronic Texts Association has created a Siddhaṃ font for their electronic version of the Taisho Tripiṭaka, though this does not contain all possible conjuncts. The software Mojikyo also contains fonts for Siddhaṃ, but split Siddhaṃ in different blocks and requires multiple fonts to render a single document.
A Siddhaṃ input system which relies on the CBETA font Siddhamkey 3.0 has been produced.
Unicode
    
Siddhaṃ script was added to the Unicode Standard in June 2014 with the release of version 7.0.
The Unicode block for Siddhaṃ is U+11580–U+115FF:
| Siddham[1][2] Official Unicode Consortium code chart (PDF) | ||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
| U+1158x | 𑖀 | 𑖁 | 𑖂 | 𑖃 | 𑖄 | 𑖅 | 𑖆 | 𑖇 | 𑖈 | 𑖉 | 𑖊 | 𑖋 | 𑖌 | 𑖍 | 𑖎 | 𑖏 | 
| U+1159x | 𑖐 | 𑖑 | 𑖒 | 𑖓 | 𑖔 | 𑖕 | 𑖖 | 𑖗 | 𑖘 | 𑖙 | 𑖚 | 𑖛 | 𑖜 | 𑖝 | 𑖞 | 𑖟 | 
| U+115Ax | 𑖠 | 𑖡 | 𑖢 | 𑖣 | 𑖤 | 𑖥 | 𑖦 | 𑖧 | 𑖨 | 𑖩 | 𑖪 | 𑖫 | 𑖬 | 𑖭 | 𑖮 | 𑖯 | 
| U+115Bx | 𑖰 | 𑖱 | 𑖲 | 𑖳 | 𑖴 | 𑖵 | 𑖸 | 𑖹 | 𑖺 | 𑖻 | 𑖼 | 𑖽 | 𑖾 | 𑖿 | ||
| U+115Cx | 𑗀 | 𑗁 | 𑗂 | 𑗃 | 𑗄 | 𑗅 | 𑗆 | 𑗇 | 𑗈 | 𑗉 | 𑗊 | 𑗋 | 𑗌 | 𑗍 | 𑗎 | 𑗏 | 
| U+115Dx | 𑗐 | 𑗑 | 𑗒 | 𑗓 | 𑗔 | 𑗕 | 𑗖 | 𑗗 | 𑗘 | 𑗙 | 𑗚 | 𑗛 | 𑗜 | 𑗝 | ||
| U+115Ex | ||||||||||||||||
| U+115Fx | ||||||||||||||||
| Notes | ||||||||||||||||
Gallery
    
This is a gallery of example usages of the Siddham script.
 A reproduction of the palm-leaf manuscript in Siddham script, originally held at Hōryū-ji Temple, Japan; now located in the Tokyo National Museum at the Gallery of Hōryū—ji Treasure. The original copy may be the earliest extant Sanskrit manuscript of the Heart Sutra dated to the 7th–8th century CE. It also contains the Sanskrit text of the Uṣṇīṣa Vijaya Dhāraṇī Sūtra and the final line shows the Siddhaṃ abugida.[17] A reproduction of the palm-leaf manuscript in Siddham script, originally held at Hōryū-ji Temple, Japan; now located in the Tokyo National Museum at the Gallery of Hōryū—ji Treasure. The original copy may be the earliest extant Sanskrit manuscript of the Heart Sutra dated to the 7th–8th century CE. It also contains the Sanskrit text of the Uṣṇīṣa Vijaya Dhāraṇī Sūtra and the final line shows the Siddhaṃ abugida.[17]
 Chinese use of the Siddhaṃ script for the Pratisara mantra, from the Later Tang. 927 CE Chinese use of the Siddhaṃ script for the Pratisara mantra, from the Later Tang. 927 CE
 Chinese use of the Siddhaṃ script for the Mahāpratyaṅgirā mantra. 971 CE Chinese use of the Siddhaṃ script for the Mahāpratyaṅgirā mantra. 971 CE
 
 Mirror with bijaksharas, Miyajima Mirror with bijaksharas, Miyajima
 A stone inscription of the Buddhist Uṣṇīṣa Vijaya Dhāraṇī Sūtra at Asakusa Temple in Tokyo using Siddham script. A stone inscription of the Buddhist Uṣṇīṣa Vijaya Dhāraṇī Sūtra at Asakusa Temple in Tokyo using Siddham script.
 Siddhaṃ alphabet by Kūkai (774–835) Siddhaṃ alphabet by Kūkai (774–835)
 A Buddhist altar in Kawasaki, Japan showing a devotional mantra inscribed in Siddham to Shakyamuni Buddha with Japanese pronunciation guide A Buddhist altar in Kawasaki, Japan showing a devotional mantra inscribed in Siddham to Shakyamuni Buddha with Japanese pronunciation guide
 Shorter Sukhāvatīvyūha Sūtra written in katakana, Siddhaṃ scripts and kanji. This book was published in 1773 in Japan. Shorter Sukhāvatīvyūha Sūtra written in katakana, Siddhaṃ scripts and kanji. This book was published in 1773 in Japan.
Notes
    
- Its usage survives into the modern period for liturgical purposes in Japan and Korea.
References
    
    Citations
    
- Singh, Upinder (2008). A History of Ancient and Early Medieval India: From the Stone Age to the 12th Century. Delhi: Pearson. p. 43. ISBN 9788131716779.
- https://archive.org/details/epigraphyindianepigraphyrichardsalmonoup_908_D/mode/2up,p39-41
- Malatesha Joshi, R.; McBride, Catherine (11 June 2019). Handbook of Literacy in Akshara Orthography. ISBN 9783030059774.
-  Daniels, P.T. (January 2008). "Writing systems of major and minor languages". {{cite journal}}: Cite journal requires|journal=(help)
- Masica, Colin (1993). The Indo-Aryan languages. p. 143.
- Handbook of Literacy in Akshara Orthography, R. Malatesha Joshi, Catherine McBride (2019), p. 27.
- Monier-Williams Sanskrit-English Dictionary, page 1215, col. 1 http://www.sanskrit-lexicon.uni-koeln.de/monier/
- Rajan, Vinodh; Sharma, Shriramana (2012-06-28). "L2/12-221: Comments on naming the "Siddham" encoding" (PDF). Retrieved 2014-08-19.
- "Devanagari: Development, Amplification, and Standardisation". Central Hindi Directorate, Ministry of Education and Social Welfare, Govt. of India. 3 April 1977. Retrieved 3 April 2018 – via Google Books.
- Pandey, Anshuman (2012-08-01). "N4294: Proposal to Encode the Siddham Script in ISO/IEC 10646" (PDF). Working Group Document, ISO/IEC JTC1/SC2/WG2.
- Salomon, Richard (1998). Indian Epigraphy. Oxford University Press. ISBN 978-0-19-535666-3.
- Handbook of Literacy in Akshara Orthography, R. Malatesha Joshi, Catherine McBride(2019)
- Kawabata, Taichi; Suzuki, Toshiya; Nagasaki, Kiyonori; Shimoda, Masahiro (2013-06-11). "N4407R: Proposal to Encode Variants for Siddham Script" (PDF). Working Group Document, ISO/IEC JTC1/SC2/WG2.
- SM Dine, 2012, Sanskrit Beyond Text: The Use of Bonji (Siddham) in Mandala and Other Imagery in Ancient and Medieval Japan, University of Washington.
- Siddhaṃ : the perfect script.
- Buddhism guide: Shingon.
- e-museum 2018 Ink on pattra (palmyra leaves used for writing upon) ink on paper Heart Sutra: 4.9x28.0 Dharani: 4.9x27.9/10.0x28.3 Late Gupta period/7–8th century Tokyo National Museum N-8.
Sources
    
- Bonji Taikan (梵字大鑑). (Tōkyō: Meicho Fukyūkai, 1983)
- Chaudhuri, Saroj Kumar (1998). Siddham in China and Japan, Sino-Platonic papers No. 88
- e-Museum, National Treasures & Important Cultural Properties of National Museums, Japan (2018), "Sanskrit Version of Heart Sutra and Viyaya Dharani", e-Museum
- Stevens, John. Sacred Calligraphy of the East. (Boston, MA: Shambala, 1995.)
- Van Gulik, R.H. Siddham: An Essay on the History of Sanskrit Studies in China and Japan (New Delhi, Jayyed Press, 1981).
- Yamasaki, Taikō. Shingon: Japanese Esoteric Buddhism. (Fresno: Shingon Buddhist International Institute, 1988.)
- Chandra, Lokesh (1965) Sanskrit bījas and mantras in Japan, New Delhi , International Academy of Indian Culture, BQ5125.B5 A75 1965
External links
    

- Fonts:
- Noto Sans Siddham from the Noto fonts project
- Muktamsiddham—Free Unicode Siddham font
- ApDevaSiddham—(Japanese) Free Unicode 8.0 Siddham Font (mirror)
 
- Siddham alphabet on Omniglot
- Examples of Siddham mantras Chinese language website.
- Visible Mantra an extensive collection of mantras and some sūtras in Siddhaṃ script
- Bonji Siddham Character and Pronunciation
- SiddhamKey Software for inputting Siddham characters