Horizontal writing in the middle of vertical writing


My character dictionary is written in vertical style. In this dictionary,
columns of text are sometimes divided into two smaller columns, which are read
right-then-left. I've read that this is called 割注{わりちゅう}. It looks like this:

![](https://i.stack.imgur.com/c6PSw.jpg)

This says りんれつ.

Sometimes, when there's only a single character in each column, it looks like
horizontal writing: right-to-left. Based on this experience, I figured any
horizontal writing in the middle of vertical writing would be read right-to-
left.

However, on the first page of the novel 魔術{まじゅつ}はささやく, I came across this:

![](https://i.stack.imgur.com/uGy2D.jpg)

I think it says 24. But that would be left-to-right! My intuition tells me it
should be so, because they are not Chinese or Japanese characters. But is this
really correct? My experience with my dictionary tells me it might say 42
instead. Which is it?

More generally, how do I tell which way to read horizontal writing in the
middle of vertical writing?




Numbers and sometimes short Latin alphabet words (like abbreviations) escape
this rule. Even in 割注, I would always read numbers and Latin-alphabet words
the "usual" way (which I think of as left-to-right and top-to-bottom, in this
order).

I make sense of it like this:

For vertical writing it is `top-to-bottom -> right-to-left`.  
For horizontal writing it is `left-to-right -> top-to-bottom`.

For horizontal writing, `left-to-right` comes first, so two characters should
be typeset next to each other, read from left to right.

For vertical writing,`top-to-bottom` comes first, so two characters should be
typeset one on top of the other first.

Breaking the column after a single character to type the next character in a
separate column doesn't make much sense, so if text is typeset in a single
line, it should be read left-to-right. If text is typeset in a single column,
there is no confusion. In both vertical and horizontal writing, only the rule
top-to-bottom applies.




Numbers and sometimes short Latin alphabet words (like abbreviations) escape
this rule. Even in 割注, I would always read numbers and Latin-alphabet words
the "usual" way (which I think of as left-to-right and top-to-bottom, in this
order).

I make sense of it like this:

For vertical writing it is `top-to-bottom -> right-to-left`.  
For horizontal writing it is `left-to-right -> top-to-bottom`.

For horizontal writing, `left-to-right` comes first, so two characters should
be typeset next to each other, read from left to right.

For vertical writing,`top-to-bottom` comes first, so two characters should be
typeset one on top of the other first.

Breaking the column after a single character to type the next character in a
separate column doesn't make much sense, so if text is typeset in a single
line, it should be read left-to-right. If text is typeset in a single column,
there is no confusion. In both vertical and horizontal writing, only the rule
top-to-bottom applies.

