* The strings: The poem opens with the speaker describing the "old six strings" that "creaked and whined" like his father's "tired back." The strings represent the father's physical limitations and the wear and tear of his life.
* The body: The guitar's "body of polished wood" represents the father's physical presence, while the "crack in the wood" symbolizes the father's vulnerability and the hardships he has endured.
* The music: The music produced by the guitar represents the father's love, passion, and expression. The "rough notes" suggest a life filled with challenges and struggles, while the "gentle melody" hints at the beauty and tenderness that he also possesses.
* The tuning: The speaker mentions the father's "old hands" that "knew the right pitch" for tuning the guitar, highlighting his wisdom and understanding of the world. This suggests the father's ability to find harmony and order amidst the chaos of life.
* The craftsmanship: The guitar's "handmade" nature symbolizes the father's hard work and dedication. He built a life, just as a craftsman builds a guitar, with care and precision.
This extended metaphor allows Espada to explore the complexities of the father-son relationship, highlighting the father's strength, resilience, and the love that binds them together. The poem also uses the guitar as a symbol of the father's heritage and cultural identity, emphasizing the importance of music and tradition in the speaker's life.