勉学 and 自習: study as an undertaking and self-study
Compare devotion to studies with studying on one's own initiative, distinguishing the scope of study from the way of learning.
Studies as an undertaking with 勉学
勉学 (べんがく) refers to study as an undertaking. The example 「彼は働きながら勉学に励んでいる。」 is translated as “He is devoted to his studies while working.” Read the circumstances of the studies without restricting the word to a particular location.
The example 「奨学金のおかげで、私は勉学を続けられた。」 is translated as “The scholarship allowed me to continue my studies.” The scholarship made continued study possible. That does not specify the particular learning method used each day.
Self-study with 自習
自習 (じしゅう) refers to self-study. The example 「放課後に図書室で一時間自習した。」 is translated as “I studied on my own for an hour in the library after school.” Identify the self-directed way of studying and the content addressed.
The example 「自習の時間に分からない問題を整理した。」 is translated as “During self-study time, I organized the problems I did not understand.” Self-study alone does not establish that nobody is nearby or that no materials or help are used.
Self-study within one's studies
勉学 presents the broader undertaking of study; 自習 presents a self-directed way of studying. Self-study can be part of one's studies rather than an activity outside them.
Read who directs the learning and what is studied. Keep the stated time and place without making all self-study necessarily solitary.
Can learning through 自習 also be part of 勉学?
Show the answer and why
Yes. 勉学 names the broader undertaking of studies, while 自習 names a self-directed method. Self-study can contribute to one's studies and does not by itself imply being alone or receiving no help.