first-stage examination; primary exam
Refers to the initial screening or qualifying exam in a multi-stage selection process, such as university entrance, professional licensing, or job recruitment.
If I pass the first-stage exam, I'll start preparing for the second-stage exam.
二次試験 is the second-stage or final exam that follows 一次試験 in a multi-stage process.
Common First-Stage Exam; Joint First-Stage Achievement Test
Compound of 一次 (first, primary) and 試験 (examination).