反面but on the other hand
One thing has two sides that pull in opposite directions, usually a good one and a bad one. You grant the first, then bring in the second.
This medicine works well, but it also has strong side effects.
How to form it
Plain form + 反面
A な-adjective keeps な: 便利な反面. A noun takes である. その反面 opens a new sentence.
- Before it
- One side of something, usually the good one: convenient, effective, rewarding.
- After it
- The other side of the same thing, often with も: the cost, the risk, the worry.
- Tone
- Fair-minded. You are weighing something up, not complaining about it.
- Where you'll meet it
- Essays, reviews, reports and exam reading passages. In conversation people mostly say けど.
In use
This town has good transport, but rents are high.
Transport and rents are two sides of one thing, the town.
I find the new job rewarding, but I'm also anxious about how much responsibility it carries.
This material is light and strong. On the other hand, it doesn't stand up well to heat.
This job is hard, but it is rewarding too.
The bad side can come first.
One thing, two opposite sides
English "on the other hand" can turn to a different person or simply add another fact. 反面 stays with one thing, the same town, job or person, and the second half has to pull against the first.
Not said: 兄は
(My older brother is quiet, whereas my younger brother talks a lot.)
Two different people, so it is 静かなのに対して.
Not said: 彼は
(He works for a company, and on weekends he also teaches soccer.)
Nothing here pulls against anything, so it is 働く一方で.
Close neighbours
に対してN3
Two different things side by side: A is like this, B is like that.
My older brother is quiet, whereas my younger brother talks a lot.
一方（で）N3
It fits two different things, two sides of one thing, and one person doing two things, so it does not say which kind of pair this is. 反面 and に対して do.
My older sister works during the day and also goes to school at night.
Check yourself
1Which one fits?
一人
Choose an answer to see why.
2Which one fits?
彼女は
Choose an answer to see why.
More detail
It is also written 半面. Here it follows a noun, with である:
Online classes are a flexible way to learn, but it can also be hard to stay focused.
More sentences
This software is easy to use, but it isn't suited to fine-tuning the settings.
Remote work cuts commuting time, but you tend to have less contact with colleagues.
This system gives users greater freedom. On the other hand, managing yourself becomes more important.