In just a few short lines, the poem pictures letters sent in wartime, and the picture is stark: "white and char." The white is the blank page, the char is what burns or blackens, whether ink, ash, or something destroyed. Together they suggest paper that carries both hope and damage. The idea that these letters "stop time" is open to a few readings. A letter can hold a moment still, or it can make the wait for news feel endless.
Then the poem turns on the word "But." The last two lines, "we dine / on ice," shift to the people left behind, or to the speaker and someone else. Eating ice gives no nourishment and no warmth, so it points to a cold, empty kind of survival. Judging by the imagery, the speaker feels numb, helpless, and shut out from ordinary life. The mood is chilly and tense, and the clipped rhymes (war, time, dine, ice) make it feel tight and held-in, like words spoken through clenched teeth.