１いち万まん

い

ち

ま

ん

Meanings

1

10,000; ten thousand

The basic Japanese numeral for ten thousand; used in counting, prices, and quantities.

会かい場じょうには１いち万まん人にんが集あつまった。

Ten thousand people gathered at the venue.

千せんN5
千 means 1,000, one order of magnitude smaller than １万, which means 10,000.
十じゅう万まん
十万 means 100,000, one order of magnitude larger than １万, which means 10,000.

一いち億おくN5
一万 is 10,000, while 一億 is 100,000,000 — learners sometimes mix up the scale between the two large-number terms.

１いち万まん
Standard modern numeral-kanji spelling; very common in everyday writing.
一いち万まん
Full kanji spelling; common in formal or vertical writing.
１００００いちまん
All-numeral spelling; used in contexts like prices or statistics.
一〇〇〇〇いちまん
Kanji-zero spelling; rarely used, mainly in vertical or formal documents.

Compound of 一 (いち, 'one') and 万 (まん, 'ten thousand'). The reading いちまん is regular.