矢先(やさき)arrowhead, target of a flying arrow, brunt (of an attack), the very moment (when), the point (of doing)

その兵士(へいし)は矢先(やさき)が心臓(しんぞう)に刺(さ)さって死(し)んだ。

The soldier died with the arrowhead piercing his heart.

臆病(おくびょう)な武士(ぶし)が矢先(やさき)から安全(あんぜん)な場所(ばしょ)へ逃(に)げました。

The cowardly samurai fled from the target of a flying arrow to a safe place.

退勤(たいきん)しようとした矢先(やさき)に上司(じょうし)に呼(よ)び止(と)められて不機嫌(ふきげん)になった。

I became upset when my boss called me back at the very moment I was about to leave work.

出(で)かけようとした矢先(やさき)にインターホンが鳴(な)り、つい溜(た)め息(いき)が出(で)ました。

Just as I was about to go out, the intercom rang, and I let out a sigh.

人生(じんせい)を楽(たの)しんでいた矢先(やさき)に急死(きゅうし)するとは…彼(かれ)はさぞ未練(みれん)だったことでしょう。

To think he died suddenly at the very moment when he was enjoying life... He must have had many regrets.