-----------------------------------
旅立つ, たびだつ
1. to begin a trip, to depart, to embark
2. to die, to pass away, to depart this life
启程,出发,启航;死去,逝去,离开人世
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题;表示与另一选项(无论是否明确提及)形成对比;表示强调