Confusion on the politeness vs. formality terminology


I was reading the "Dictionary of Japanese Grammar" series, and I found the way
it uses the term formality vs. politeness contradictory and confusing, so I
wanted some clarifications.

Here are some examples:

From the "Basic" volume, page 43:

[![enter image description
here](https://i.stack.imgur.com/B0cWi.png)](https://i.stack.imgur.com/B0cWi.png)

From the "Advanced" volume, page 35:

[![enter image description
here](https://i.stack.imgur.com/J4eAC.png)](https://i.stack.imgur.com/J4eAC.png)

In the "Basic" volume, だ is said to be informal, while です is said to be
formal. On the other hand, the "Advanced" volume defines だ<->です as a
plain<->polite pair, but they both are categorized as informal. To add to the
confusion, there is this quote:

[![enter image description
here](https://i.stack.imgur.com/tZUzv.png)](https://i.stack.imgur.com/tZUzv.png)

Which once again contradicts the chart from the first volume of the series.
This is especially confusing, because in every resource that I have read
(including the verb conjugation chart at the end of the "Basic" volume), the
-ます form is the formal form of a verb.

And it never mentions how all of this fits into the 丁寧語・尊敬語・謙譲語 framework
either.

So can anyone help me reconcile these contradictions? Also if possible, can
anyone point me to a detailed resource on Japanese formality & politeness and
how it fits into the 敬語 framework, preferably in English? I tried to look
around, but all of them tends to be really shallow and contains few examples.
I liked the in-depth style of DoJG explanations, but the contradictions above
plus the fact that they completely excluded 敬語 left me wanting for more.




If these are really from two volumes of the same edition, I have to say this
is indeed confusing and misleading. 食べた is perfectly valid in formal articles.
As for the terminology, I see the following names most often:

  * だ: Plain form (can be formal or informal)
  * です: Polite form (usually formal, too)
  * (である: Literary/stiff form)

In Japanese, だ/である is called 常体 and です/ます is called 敬体.

Regarding the formality vs politeness, I think formality is easier because
English has this distinction, too ( _child_ vs _kid_ , _yes_ vs _yeah_ ).
However, Japanese has two styles even in formal settings.

In formal settings, politeness is a sign of humanity and friendliness, so you
need it when you communicate with your business partners and customers. On the
other hand, the plain form in formal settings is a sign of dignity,
academicity and matter-of-factness, and you use it to write a plain news
article, an academic manuscript, a rule book, a Wikipedia article, etc.

