The outbreak of war between Russia and Japan in 1904 through Japanese torpedo boats attacking Russian men-of-war at Port Arthur before a formal declaration of war, caused a movement for the establishment of some written rules concerning the commencement of war. The Institute of International Law, at its meeting at Ghent in 1906, adopted three principles[176] according to which war should not be commenced without either a declaration of war or an ultimatum, and in either case a certain delay sufficient to ensure against treacherous surprise must be allowed before the belligerent can have recourse to actual hostilities. The Second Peace Conference at the Hague in 1907 took the matter up and produced the Convention (III.) relative to the commencement of hostilities which comprises four articles and has been signed by all the Powers represented at the Conference, except China and Nicaragua, both of which, however, acceded later. [Footnote 172: See Maurice, _Hostilities without Declaration of War_ (1883).] [Footnote 173: See, for instance, Vattel, III. § 51; Calvo, IV. § 1907; Bluntschli, § 571; Fiore, III. No. 1274; Heffter, § 120.] [Footnote 174: See, for instance, Bynkershoek, _Quaestiones juris publici_, I. c. 2; Klüber, § 238; G. F. Martens, § 267; Twiss, II. § 35: Phillimore, III. §§ 51-55; Hall, § 123; Ullmann (first edition), § 145; Gareis, § 80.] [Footnote 175: See above, § 3, where the rule is quoted that no State is allowed to make use of compulsive means of settling differences before negotiation has been tried.] [Footnote 176: See _Annuaire_, XXI. (1906), p. 283.] [Sidenote: Declaration of War.] § 94. According to article 1 of Convention III. hostilities must not commence without a previous and unequivocal warning, and one of the forms which this warning may take is a declaration of war stating the reasons why the Power concerned has recourse to arms.