Unicode Numeral Systems

As part of my investigations into Machin stamps, I started looking at numeral systems for labelling stamp denominations and also clock faces.

Unicode 13.0.0 contains a few General Categories used to classify code points according to numeric value ("Nd", "Nl" & "No") plus Derived Numeric Types ("Decimal", "Digit" & "Numeric"). Trawling through these and the Wikipedia pages on numeral systems, I came up with well over one hundred systems that can be used to represent numbers in Unicode using single glyphs:

Unicode Numerals web page

As it turns out, this experiment became more of an exercise in font management. I initially used Unifont for rendering, but this is quite ugly. The Code2000 fonts are no longer maintained. I ended up using Googles Noto fonts. However, there doesn't seem to be a definitive list of which glyphs exist in which font, so I had to create a tool to interrogate all the Noto web fonts I could find. Even an online list of those web fonts seems lacking, so here's one:

• Noto Kufi Arabic
• Noto Naskh Arabic
• Noto Naskh Arabic UI
• Noto Nastaliq Urdu
• Noto Sans
• Noto Sans JP
• Noto Sans KR
• Noto Sans SC
• Noto Sans TC
• Noto Sans Adlam
• Noto Sans Adlam Unjoined
• Noto Sans Anatolian Hieroglyphs
• Noto Sans Arabic
• Noto Sans Arabic UI
• Noto Sans Armenian
• Noto Sans Avestan
• Noto Sans Balinese
• Noto Sans Bamum
• Noto Sans Batak
• Noto Sans Bengali
• Noto Sans Bengali UI
• Noto Sans Bhaiksuki
• Noto Sans Brahmi
• Noto Sans Buginese
• Noto Sans Buhid
• Noto Sans Canadian Aboriginal
• Noto Sans Carian
• Noto Sans Chakma
• Noto Sans Cham
• Noto Sans Cherokee
• Noto Sans Coptic
• Noto Sans Cuneiform
• Noto Sans Cypriot
• Noto Sans Deseret
• Noto Sans Devanagari
• Noto Sans Devanagari UI
• Noto Sans Display
• Noto Sans Egyptian Hieroglyphs
• Noto Sans Ethiopic
• Noto Sans Georgian
• Noto Sans Glagolitic
• Noto Sans Gothic
• Noto Sans Gujarati
• Noto Sans Gujarati UI
• Noto Sans Gurmukhi
• Noto Sans Gurmukhi UI
• Noto Sans Gunjala Gondi
• Noto Sans Hanifi Rohingya
• Noto Sans Hanunoo
• Noto Sans Hebrew
• Noto Sans Imperial Aramaic
• Noto Sans Indic Siyaq Numbers
• Noto Sans Inscriptional Pahlavi
• Noto Sans Inscriptional Parthian
• Noto Sans Javanese
• Noto Sans Kaithi
• Noto Sans Kannada
• Noto Sans Kannada UI
• Noto Sans Kayah Li
• Noto Sans Kharoshthi
• Noto Sans Khmer
• Noto Sans Khmer UI
• Noto Sans Khudawadi
• Noto Sans Lao
• Noto Sans Lao UI
• Noto Sans Lepcha
• Noto Sans Limbu
• Noto Sans Linear B
• Noto Sans Lisu
• Noto Sans Lycian
• Noto Sans Lydian
• Noto Sans Malayalam
• Noto Sans Malayalam UI
• Noto Sans Mandaic
• Noto Sans Masaram Gondi
• Noto Sans Mayan Numerals
• Noto Sans Medefaidrin
• Noto Sans MeeteiMayek
• Noto Sans Mende Kikakui
• Noto Sans Meroitic
• Noto Sans Modi
• Noto Sans Mongolian
• Noto Sans Mono
• Noto Sans Mro
• Noto Sans Myanmar
• Noto Sans Myanmar UI
• Noto Sans New Tai Lue
• Noto Sans Newa
• Noto Sans Ogham
• Noto Sans Ol Chiki
• Noto Sans Old Italic
• Noto Sans Old Persian
• Noto Sans Old South Arabian
• Noto Sans Old Turkic
• Noto Sans Oriya
• Noto Sans Oriya UI
• Noto Sans Osage
• Noto Sans Osmanya
• Noto Sans Pahawh Hmong
• Noto Sans Phags Pa
• Noto Sans Phoenician
• Noto Sans Rejang
• Noto Sans Runic
• Noto Sans Samaritan
• Noto Sans Saurashtra
• Noto Sans Sharada
• Noto Sans Shavian
• Noto Sans Sinhala
• Noto Sans Sinhala UI
• Noto Sans Sundanese
• Noto Sans Syloti Nagri
• Noto Sans Symbols
• Noto Sans Symbols 2
• Noto Sans Syriac
• Noto Sans Tagalog
• Noto Sans Tagbanwa
• Noto Sans Tai Le
• Noto Sans Tai Tham
• Noto Sans Tai Viet
• Noto Sans Takri
• Noto Sans Tamil
• Noto Sans Tamil UI
• Noto Sans Telugu
• Noto Sans Telugu UI
• Noto Sans Thaana
• Noto Sans Thai
• Noto Sans Thai UI
• Noto Sans Tifinagh
• Noto Sans Tirhuta
• Noto Sans Ugaritic
• Noto Sans Vai
• Noto Sans Wancho
• Noto Sans Warang Citi
• Noto Sans Yi
• Noto Serif
• Noto Serif JP
• Noto Serif KR
• Noto Serif SC
• Noto Serif TC
• Noto Serif Ahom
• Noto Serif Armenian
• Noto Serif Bengali
• Noto Serif Devanagari
• Noto Serif Display
• Noto Serif Ethiopic
• Noto Serif Georgian
• Noto Serif Gujarati
• Noto Serif Hebrew
• Noto Serif Kannada
• Noto Serif Khmer
• Noto Serif Lao
• Noto Serif Malayalam
• Noto Serif Myanmar
• Noto Serif Nyiakeng Puachue Hmong
• Noto Serif Sinhala
• Noto Serif Tamil
• Noto Serif Telugu
• Noto Serif Thai
• Noto Serif Tibetan

The Font Check tool allows you to type in a hexadecimal Unicode code point and see the fonts that can render it. It uses the trick of measuring the glyph using an offscreen canvas with a fallback font of Adobe Blank. If the glyph is zero pixels wide, it means it was rendered using the fallback (or is naturally zero-width, so isn't of interest to us anyway).

Using the tool, I worked out the minimal set of Noto fonts needed to render the numerals table. However, there were a few issues:

1. Some fonts only come in serif variants, not sans serif (and vice versa).
   
   
2. I couldn't find any Noto web fonts that could render the following (though the asterisked scripts were rendered correctly using a fallback font by my browser):
   
   
• Dives Akuru
• Khmer Divination*
• Myanmar Tai Laing*
• Nko*
• Ottoman Siyaq
• Sinhala*
• Sora Sompeng*
• Tag
  
  
3. Arabic Persian and Arabic Urdu use exactly the same codepoints but use different languages in the HTML mark-up to select different sets of glyphs.

Further notes:

• I couldn't find any information on how Ogham represented numbers, so I made something up based on tally marks.
• The Tibetan script has a parallel set of numerals for half values; they're used in stamps, which is a nice coincidence.
• The Runic Golden Numbers are used in Younger Futhark calendars.
• Other scripts do have numerals or counting systems, but I excluded many because they are "low radix" (e.g. native Korean)