兵(へい)士(し) heishiたち tachiは wa警(けい)戒(かい) keikaiし shiながら nagara国(こっ)境(きょう) kokkyouへ e向(む)か()っ()た() mukatta。 The soldiers headed toward the border while staying on guard. Literal Soldiers [topic-は] be-vigilant [while-ながら] border [direction-へ] headed. へ向かった ('headed toward') is a simpler phrasing than the longer に向かって進んだ — the へ alone marks direction without an extra 進む. ~ながら links the simultaneous actions of being vigilant and advancing. military~ながら (while doing)
兵(へい)士(し) heishiたち tachiは wa警(けい)戒(かい) keikaiし shiながら nagara国(こっ)境(きょう) kokkyouへ e向(む)か()っ()た() mukatta。 The soldiers headed toward the border while staying on guard. Literal Soldiers [topic-は] be-vigilant [while-ながら] border [direction-へ] headed. へ向かった ('headed toward') is a simpler phrasing than the longer に向かって進んだ — the へ alone marks direction without an extra 進む. ~ながら links the simultaneous actions of being vigilant and advancing. military~ながら (while doing)