Matches spans near the beginning of a field. The span first query maps to Lucene SpanFirstQuery. Here is an example:

GET /_search
{
  "query": {
    "span_first": {
      "match": {
        "span_term": { "user.id": "kimchy" }
      },
      "end": 3
    }
  }
}

The match clause can be any other span type query. The end controls the maximum end position permitted in a match.