I'm well aware that when someone says "he's the one who calls the shots" it means that that person is the one in charge, the one who takes all the relevant decisions.
But what's the origin of this figure of speech?
It appears to be a fairly recent phrase. The OED (sense 7.i. of shot) says it's originally and chiefly U.S. with a first quotation from 1967 in Elliot Liebow's Tally's Corner:
Sea Cat made no secret of the fact that Gloria was calling the shots in this relationship.
There's a number of results in Google Books before 1967, possibly back to 1917, but the earliest I could confirm is this literal use from 1943 in The Life of Johnny Reb: The Common Soldier of the Confederacy by Bell Irvin Wiley:
Occasionally the Yankees would interfere with culinary activities. In one instance during the Atlanta campaign Federal artillery opened on a group of Rebs as they were cooking their noon meal. One of the number was sent to a point of observation to call the shots so that the cooks could lie down after each salvo until the shells passed over.
Here, a soldier is literally calling out that shots are coming to warn the others.
And an interesting use from the same year, in Popular Mechanics (Oct 1943 - Page 69, Vol. 80, No. 4):
He [the picture control operator] watches a cathode ray oscillograph to keep track of the wave shape patterns, and switches the transmitter feed from one camera to the other as the director calls the shots.
This is interesting. It's literal: the director is vocally telling what the camera should be shooting, but it's also the same as the figurative use: the director is in charge and decides what is shown.
There's also three uses in Volume 16 (November 29 - December 20, 1943) of the hearings with testimony for the Investigation of un-American propaganda activities in the United States. Each is used by Mr. Myer giving evidence on Tule Lake internment camp for Japanese Americans.
I am getting a little brain fagged, Mr. Congressman. I am not sure I have called all my shots, but I think those are the major differences, as I can remember them.
Mr. MYER. My only comment is this, Mr. Congressman, that it is much easier for a kibitzer, after a thing is over, to call the shots than it is for a man on the job to call the shots.
Myer continues further down the page:
I do not thingk that any general would tell you that the best time to attack is when the enemy seemed to be in reasoable control of the situation. I would rather call my own shots. I was not in a position to call----
Both its literal and figurative uses can be found later in the 1940s.
There's a number of earlier examples, but they appear only in snippets and Google may have got the date wrong. But, taken as a whole, they show a kind of evolution of the phrase.
Arms and the Man (Volume 63 - Page 427 - an precursor to the NRA's American Rifleman) uses the phrase twice. First:
.. make such groups with service sights but from the ease with which I can call the shots I should judge this to be the case. At 200 yards on one occasion I had one fellow declaring emphatically that I could see the bullet holes as I spotting pretty fair that day with 15.
This custom with him arose because, he declared, he could not call the shots made with ground bullets as successfully as he could call those made with patched bullets.
Both of these suggest someone judging how well shots from a gun hit a target.
The same publication uses it in a similar way the next year in volume 64:
Then Harker stood near the target, to call the shots, his point of observation being some 20 feet to right and same distance to the rear. Bruce walked deliberately to the firing point and squared himself for the trials, with his favorite Remington in his trusty right grip and ten cartridges in his left.
1922, 1923, 1931, 1936
Later uses include calling the result of shooting firearms:
Or announcing the intended hole in pool or billiards:
Or judging another sports result:
There appears to be a variety of supposed origins, military ancient and modern, billiards, hunting, floating logs down North American rivers... There's also this which goes back a bit:
... the term "call the shots" dates from the early 1500s when curling was first played in Scotland. The "skip" (team leader) "calls" the shot for his player i.e. distance, speed and line.
This is dated 7 March 2011 and is found on www.english-test.net.
In whisky making, the beginning of the distillation process produces undesirable volitiles that begin boiling off before the desired ethanol starts vaporizing. Because this essentially poisonous liqour is produced at the beginning of a distillation run it's referred to as the "foreshots". The "aftershot" consists of what boils off at the end of the distillation run,though non-poisonous, it isn't suitable for consumption either. "Calling the shots" is essentially the art of knowing what part of the distillation run to retain and what parts (foreshots/aftershots) are to be discarded.