反省 and 復習: reviewing behavior and revisiting learned material
Compare reflection on lateness or a game with reviewing learned grammar or mistaken questions. Identify the object of each activity, the next-practice purpose, and the proposal to review only mistakes.
Looking back at one's own behavior
反省 (はんせい) includes reflection and remorse. 「遅刻した理由を考え、行動を反省した。」 means “I considered why I was late and reflected on my behavior.” The object being examined is the person's behavior, rather than previously learned grammar.
「試合後の反省を次の練習に生かす。」 is translated as “We will apply what we learned from reflecting on the game to our next practice.” It connects reflection on the game with the next practice. It does not report an already achieved improvement in skill or a result in the next game.
Studying previously learned material again
復習 (ふくしゅう) means review. 「授業で習った文法を家でもう一度復習した。」 means “I reviewed the grammar I had learned in class again at home.” This is a past review of learned grammar, with a different object from reflection on being late.
「試験の前に間違えた問題だけを復習しよう。」 means “Before the test, let us review only the questions we got wrong.” Preserve both the mistaken questions and the limit expressed by “only.” The proposal does not report completed review or a review of every question.
Identify the object rather than a degree of feeling
The useful distinction here is behavior or game performance being examined versus learned grammar or questions being studied again. Reducing 反省 to stronger regret or 復習 to memory alone misses that difference. Reflection applied to practice and review of learned material can also occur together.
Do not choose the words solely by whether an activity happens before or after a class, or how often it is repeated. First identify what is being examined or revisited, then preserve the next-practice purpose and the proposal to review. A completed review and a proposal for review remain different statements.
What is being examined when someone reflects on being late, and what is being revisited in a proposal to review only mistaken questions?
Show the answer and why
反省 examines the person's behavior. 復習 revisits mistaken questions from learned material. The latter is a proposal limited to those questions, rather than a report that every question has already been reviewed.