Hi Hans,

I modified the part of Chinese numeral conversion in core-con.lua script.
The attachment is the patch. After many tests as the following I think the
patch is right even though it looks dirty.

%%%%
\definefont[song][name:adobesongstdlight]\song
\starttext

\startluacode
local function test (cs)
    j = 1
    for i = 1, 9 do
        tex.print (j .. ': ' .. '\\chinesenumerals{' .. j .. '}\\par')
        j = j * 10 + 1
    end
    tex.print ('\\blank')
end

test ('\\chinesenumerals')
test ('\\chinesecapnumerals')
test ('\\chineseallnumerals')
\stopluacode

This is test for chinese zero:

\startluacode
j = 1
for i = 1, 9 do
    tex.print (j .. ': ' .. '\\chinesenumerals{' .. j .. '}\\par')
    if i % 2 == 0 then
        j = j * 10
    else
        j = j * 10 + 1
    end
end
\stopluacode

\stoptext


The pdf in attachments is output result.

-- 
Best regards,

Li Yanrui