First Installment
First Round, First Wave
noun
The ordinal number prefix one bullet is actually the first installment of something. Picture someone firing a gun to let everyone know that, yes, this is indeed the first round of… whatever you're doing.
Note that this is quite similar to 第一段. While 第一段 refers to the first phase or step within one larger, continuous process or structure, 第一弾 is used to refer to the first installment or part of a series of events or releases.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
シリーズの第一弾
first installment of the series
企画の第一弾
the first round of a series of projects
限定商品の第一弾
the first release of a limited product series
キャンペーンの第一弾
the first round of a promotional campaign
我が社とWaniKaniとのコラボ商品第一弾は、ワニカニのフィギュアです！
The first product of our collaboration with WaniKani is a WaniKani figure!
こちらのイラストは、ウサギのDJシリーズの第一弾です。
This illustration is the first one in the Rabbit DJ series.
キャンペーンの第一弾の反応を見て、第二弾の中身を調整しましょう。
Let's adjust the contents of the second round by looking at the feedback to the first round of the promotional campaign.