Using only subtle foreshadowing, Shirley Jackson builds tension by providing only sparse and seemingly harmless details without an explanation of the purpose or the methods of the lottery, and this ambiguity created by withholding information continues until the very end of the story.
In the beginning of the narrative, seemingly innocuous actions are described that foreshadow what is to come, such as the children, who are recently out of school, engaging in "boisterous play," as they still talk of teachers and the classroom while they gather stones. The men come together, only discussing planting and the rain and other farm-related topics. Mr. Summers, who is described as "jovial" arrives with a black box; he is described only as a man who has "time and energy to devote to civic activities."
Further in the narrative details are provided are rather foreboding and generate tension. For instance, when Bobby Martin, who has already "stuffed his pockets full of stones," runs back to the pile of stones, his father sharply beckons him to take his place between him and his oldest brother. Then, when Mr. Summers requests help with the black box that he brings with him, there is "a hesitation before two men...came forward"; furthermore, while Mr. Summers mixes the papers inside this box, the box is described as being so significant that it is kept in a safe the rest of the year.
After the introduction of the black box into the narrative, the narrator mentions that there has been a "ritual" and ritualistic proceedings involving salutes and songs before each head of a household comes forward and draws from the box. But, as the "ritual" begins, people appear tense and nervous, saying that other towns have discontinued their lotteries. These details create further tension as they suggest that this ritual is not a pleasant one. Then, Mrs. Dunbar, whose husband has broken his leg, says "regretfully" that she must "fill in for the old man this year," and when Mr. Summers asks if the Watson boy is going to draw for his mother and himself, there is, ominously, no mention of Mr. Watson. Right before Mr. Summers begins to read off the names, "a sudden hush fell on the crowd." Tension increases as men move forward, but they grin at one another "humorlessly and nervously." Certainly, the actions and speech of Mrs. Hutchinson, who repeatedly protests that her husband's drawing was not fair, suggest that there is something sinister about this lottery. Finally, there is a powerful indication of the hideous intent of the lottery as Jackson writes,
Although the villagers had forgotten the ritual and lost the original black box, they still remembered to use stones. The pile of stones the boys had made was ready....Mrs. Delacroix selected a stone so large she had to pick it up with two hands....
Still, it is not until the final sentence that the reader fully understands the purpose of the lottery.