What exactly did Chekhov write in the 1889 letter that is said to contain the "gun" rule, and is the popular wording ("a gun on the wall in act one must fire") in it?

The only Chekhov-authored text in these sources is a letter of 1 November 1889 to A. S. Lazarev (Gruzinsky) about a vaudeville manuscript. It says one may not put a loaded gun on the stage if nobody means to fire it, then adds "one may not promise"; the "gun" is a figure for an unrelated opening monologue that promises the audience something the play does not deliver. The popular sentence about a pistol on the wall in act one comes from a different source (Gurlyand, as quoted in the editors' note), not from the letter. The Constance Garnett letters volume does not contain this letter. Curator qualifications: Wikitext (ё normalised to е): 'Нельзя ставить на сцене заряженное ружье, если никто не имеет в виду выстрелить из него' 2 hits (letter and commentary lemma); 'Нельзя обещать' 1. Commentary: 'Эту мысль Чехов высказал еще летом 1889 г. в Ялте в беседе с И. Я. Гурляндом: «Если Вы в первом акте повесили на стену пистолет, то в последнем он должен выстрелить. Иначе — не вешайте его» (Арс. Г. Из воспоминаний об А. П. Чехове. — «Театр и искусство», 1904, № 28, 11 июля, стр. 521)'. 'Гурлянд' 12 hits. Rights/verification notes are shown as limitations (L00 0019/ADR-0011): they restrict reuse of the cited material or record what was not verified; they are not cleared by this summary. Limitations: [rights_conflict_record] Rights hold: the editorial commentary is 20th-century scholarly matter re-hosted on Wikisource (producer rights conflict); quote briefly. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

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  "citations": [
    {
      "url": "https://ru.wikisource.org/wiki/%D0%9F%D0%B8%D1%81%D1%8C%D0%BC%D0%B0._(%D0%9E%D0%BA%D1%82%D1%8F%D0%B1%D1%80%D1%8C_1888_-_%D0%B4%D0%B5%D0%BA%D0%B0%D0%B1%D1%80%D1%8C_1889)_(%D0%A7%D0%B5%D1%85%D0%BE%D0%B2)",
      "note": "ru.wikisource Letters (Oct 1888-Dec 1889), oldid 5658775, raw wikitext; Garnett letters (Gutenberg 6408), producer negative"
    },
    {
      "url": "https://www.gutenberg.org/cache/epub/6408/pg6408.txt",
      "note": "ru.wikisource Letters (Oct 1888-Dec 1889), oldid 5658775, raw wikitext; Garnett letters (Gutenberg 6408), producer negative"
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