Why use 「一〇点」 instead of 「十点」 and how do I read it?

Question

I'm reading the Japanese version of Harry Potter and the Philosopher's Stone. When Oliver Wood is explaining Quidditch rules to Harry, he says:

輪に入るたびに一〇点だ。

Why say 「一〇点」 instead of 「十点」? How do I read it? 「イチゼロテン」?「ジュウテン」？「Tenてん」？

Is this something specific to sports? The only sport I follow is football, and since I have heard weird things like commentators saying 「いちななーいちはち」 for the '17-'18 Premier League season, I suspect that might be the case.

Answer 1

I suppose you're reading the book on paper (or Kindle-like terminal), where the text is written vertically. In vertical mode, the positional notation of kanji numerals are used as much as how Arabic numerals are used in horizontal mode.

一〇点 10 points vs. 十点 ten points

It doesn't affect the pronunciation, so you're just going to read it out じゅってん (or じってん, prescriptively). Something like いちぜろてん is rarely used unless you're a pilot or the base is other than ten.

See also:

• Are kanji typically used in times and dates?
• What is the proper pronunciation for 十分/１０分? じっぷん or じゅっぷん?
• Why is 1st floor written as ikkai いっかい?