In 1968 Blas de Otero sent a letter to Professor Gregorio Salvador in which the basque poet is greatly admired by the analysis that this literary critic and linguist made of his sonnet «La Tierra», with existentialist tone. This letter stands out by the reflection on the relationship between poetic writing and the ineffable, hence the difficulty of analyzing a poem. The letter becomes even more interesting when in its last stage Otero writes a new sonnet included in the collection of poems La galerna, from which two textual variants are preserved. The two versions suppose a reworking of the motives and ideas present in the first.En 1968 Blas de Otero envió una carta al profesor Gregorio Salvador en la que el poeta vasco se muestra muy admir...