21st Divisional Artillery Instruction 18 June 1916

Copy of G.H.Q. No O.B./21, dated 16.6.1916

In para 5. Section D Chap II, Training Manual R.F.C. Part II (page 46) it is laid down that a special prefix, followed by the sheet number and map square designation of the target, will be used as a call for artillery to open fire in case of emergency or when a specially favourable target presents itself.

By O.B./114 of July 1915, para 10, the special prefix ZZ was laid down for this purpose.

In O.B./1656 of 27.5.15, the signal ZZ was introduced as a signal from a contact patrol aeroplane that Infantry was held up by wire.

To avoid confusion, the special prefix to be used as a general call for immediate concentration of artillery fire on a certain point, as directed in para. 5, pages 46, 47 R.F.C. Training Manual, Part II, will be changed to LL.

This change will come into force from midnight June 18/19. all artillery and R.F.C. units must be warned of the change before that hour.
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BM.21
94th F.A. Bde.
95th -:-
96th -:-
97th -:-
78th -:-
79th -:-
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For information and necessary action.
The call ZZ (Infantry held up by wire) for use to contact patrol aeroplane holds good.

******
Captain R.F.A.
18th June 1916. Brigade-Major 21st Divisional Artillery