What is 격국 (gyeokguk)?
What the month you were born into commands — and what we stop short of naming.
In plain words
Of the eight letters in a chart, one carries more weight than the rest: the lower letter of the month you were born in. Traditional reading starts there, and the question it asks is not “what are you like” but “what does the season put in front of you.” The answer to that question is the 격 — the frame the rest of the reading is built on.
A word about the name. 격 means the frame; 국 means the shape the whole board falls into. Together people say 격국, and in ordinary speech it usually just means “what kind of chart is this.” It is closer to a floor plan than to a personality label — it says which room you were handed, not how well you live in it.
How Bokki computes it
Every lower letter hides one to three upper letters inside it, and one of them is the heaviest — the 본기, the main one. We take the month's lower letter, pull out its main hidden stem, and ask what that element is to your day stem. The answer is one of five groups: standing with you (비겁), what you make and send out (식상), what you handle (재성), what frames you (관성), what feeds you (인성). That group is the frame we name.
Three charts, run through the actual code — each one needs an hour and a place, for the reason the next paragraph gives. Born 15 May 1990 at 12:00 in Seoul: the month branch is 巳, whose main hidden stem is Fire, and the day stem is 庚, Metal — Fire controls Metal, so the month commands the officer group. Born 2 November 1988 at 12:00 in Seoul: the month branch is 戌, main hidden stem Earth, day stem 辛, Metal — Earth generates Metal, so the month commands the resource group. Born 3 February 2001 at 12:00 in Seoul: the month branch is 丑, main hidden stem Earth, day stem 丁, Fire — Fire generates Earth, so the month commands the output group.
This reads the month branch against your day stem — and both of those can move with the hour. The month branch turns at one of the twelve 節, and the day stem turns at midnight by the sun, not by the clock, so a birth near either boundary is not settled by the date alone. Measured across 518,400 birth minutes in Seoul (1990–1999, every minute of 36 days): 1.825% land on a frame different from the one we build when no hour is given; in London it is 2.128%. The first chart above is one of them — in Seoul on 15 May 1990 the day stem is 己 until 00:27 and 庚 from 00:28, so the frame reads resource before that minute and officer after it. If you do not tell us the hour we still show a frame, built from the date alone, and those percentages are measured against exactly that. Separately, when two positions in a chart meet in a way tradition has already named, Bokki says the name: 財多身弱 when there is more to handle than strength to handle it, 官殺太旺 when there is pressure with little to digest it, 官印相生 when pressure flows into learning, 食傷生財 when what you make turns into what you are paid. Those riders switch on from measured force, not from a lookup table of chart types.
What we do not compute
Classical 격국 method has a step we skip. A reader checks whether the month's hidden stem actually surfaces in one of the four upper letters (투출), and takes a different route when it does not. Bokki does not test for that at all. We read the month's main hidden stem and stop there.
So we do not hand out the eight classical frame names. 정관격 and 편관격 both come back to us as “the officer seat”; 정재격 and 편재격 both as “the wealth seat.” We narrow to five groups, not ten names. And when the month commands the peer group, tradition often stops calling it a 격 at all and uses 건록격 or 양인격 instead — we simply call it the peer seat.
We also do not judge special charts — 종격, 화격 and the rest of the outer frames. And we never rank frames against each other. There is no “high” frame and no “low” one here: the month tells us which ground you are standing on, and that is all we claim from it.
Closing note — five groups, not eight names
In short: gyeokguk is one lookup — the main hidden stem of your month branch, read against your day stem, sorted into one of five groups. Run the three charts above through the code and three different month branches hand back three different frames — the officer seat, the resource seat, the output seat. For most people the hour never moves that answer, but not for everyone: the month branch turns at a 節 and the day stem turns at the sun's midnight, so 1.825% of Seoul birth minutes (2.128% in London) land on a different frame than the date alone gives.
What we left out is as much the point as what we kept. No 투출 check, so 정관격 and 편관격 both collapse into one officer seat instead of two named ones. No 종격, no 화격, no frame ranked above another. A floor plan tells you which room you got, not how well you live in it — that line from the top of this page is also the boundary we held while writing the code.