此格有四日：庚辰、壬辰、戊戌、庚戌。辰为天罡，戌为河魁，乃阴阳绝灭之地，故名。
There are four days for this structure:
Geng Chen
Ren Chen
Wu Xu
Geng Xu.
Chen is TianKang (possibly referring to a name of Chinese deity), Xu is HeGui (possibly another name of deity), those are the places where Yin and Yang go extinct, thus they are named so.
独除甲干，以居干之首，在辰为青龙，在戌为禄堂，有吉而无凶故也。
For the rest of the pillars, for example Jia, sits on Chen as QingLong (green dragon), and Xu as LuTang (Fortune Hall), there's only auspiciousness and no inauspiciousness, that is why.
格须叠化重逢日位，加临者众，以伏为贵。
For this structure, there must be repeating places of Day Master, with the arriving parties many, lying hidden? as noble.
经云：魁罡聚众，发福非常，主为人性格聪明，文章振发，临事果断，秉权好杀。
The classics says: Many GuiKangs gathered, one is extraordinarily successful, denotes an intelligent person, his literary works are successful and influential, he handles matters (related to government ) prudently, he has authority and commands killing.
赋云：魁罡性严有操持，而为人聪敏是也。运行身旺，发福百端，一见财官，祸患立至，或带刑煞尤甚，倘日位独处，刑冲克制重临，必是小人，刑责不巳，穷必彻骨，运临财官旺处，主防奇祸。
The odes says: GuiKang temperament is moral, he is intelligent. When luck goes to prosperous Self, he will be highly successful, once it sees Wealth and Officer, it become a severe catastrophe, especially if it sees punishment and 7K, if the Day Pillar is punished, clashed, countered or controlled repeatedly, one is a petty people, he will be punished (by the law), or he would be poor to his bones, when LP goes to Wealth and Officer, one needs to take precautions against such disasters.
若月令见财官印绶，日主一位，即以财官印食取用，虽微有破败，财官印食得位，亦无大害，须斟酌提纲，当用者取之，不可拘以小节。
If the Month Command sees Wealth, Officer or Seal, with one DayMaster, then take the Wealth, Officer, Seal or Food as the Useful God, even though it is a little broken, if Wealth, Officer, Seal or Food has the place (being used correctly), the there is no great harm, on has to consider first the Outline (month command), take what is usable, do not stick to trifle things.
This phrase explains that if the Month EB has something usable, e.g Wealth, Officer, Seal or Food, the the structure will be according to the Month EB. GuiKang is a trifle thing that should not be prioritized over the Month EB.
又曰：庚戌、庚辰二日，无官星，若魁罡重叠有情，主富高于名，但见财则不成局，岁运再见财旺之乡，祸不可测。Also it says: The days of Geng Xu and Geng Chen, without Officer star, if GuiKang is seen repeatedly, it is affectionate, it denotes Wealth higher than reputation, but once it see Wealth, it will not become a complete structure, when LP goes to places where Wealth is prosperous, disaster is immeasurable.
庚辰日生九月，虽辰戌相冲，运行南方，柱中有火，亦可言贵。
Geng Chen born in the ninth Month, even though Chen and Xu clash each other, when Luck goes to south, with fire within the pillars, it can also be regarded as noble.
庚戌日生三月，纵有官星印绶亦不用，盖庚用戌中火为官库，戊土为印，辰中癸水伤官，又泄庚气，不成格矣。
Geng Chen day born in the 3rd month, even though there is Officer star or Seal, they are not used, as Geng uses the Fire inside Xu as the storage of Officer, Wu as Seal, within Chen is Gui water Hurting Officer, it exhausts the Qi of Geng, the structure is not successful.
戊戌日无财不贵，不宜见官，若魁罡重叠有情，富贵两全。
Wu Xu day without Wealth is not noble, it's no beneficial to see Officer, if GuiKang is seen repeatedly and it is affectionate, then one will have both wealth and nobility.
壬辰日怕见财官，大喜印绶、却(怯)财与煞，岁运同。
Ren Chen Day fears seeing Wealth and Officer, it greatly favors Seal, dreads Wealth and 7K, seeing AP or LP is analyzed similarly.
又曰：辰是水库属天罡，戌是火库属地魁，辰戌相见，为天冲地击。
Also it is said: Chen is the water storage, it belongs to TianKang, Xu is the fire storage, it belongs to DiKui, When Chen and Earth see each other, it is regarded as Heaven clashes and Earth attacks.
《子平总论》云：身值天罡地魁，衰则彻骨贫寒，强则绝伦贵显。
ZiPingZhongLun says: When Self is TianKang DiKui, when weak, one is deeply in poverty, when strong, it is extremely noble.
诗曰：壬辰庚戌与庚辰，戊戌魁罡四座神，不见财官刑煞并，身行旺地贵夫伦。
The poem says: Ren Chen, Geng Xu and Geng Chen, Wu Xu as 4 GuiKang spirits, it should not see Wealth, Officer, punishment and 7K together, when Self goes to prosperous places, it is analyzed as noble.
又：魁罡四日最为先，叠叠相逢掌大权，庚戌庚辰怕官显，戊戌壬辰畏财连。
Also: GuiKang is considered foremost for the 4 days (against all other pillars), when it is seen repeatedly, one wields high authority, Geng xu, and Geng Chen is afraid of prominent Officer, Wu Xu and Ren Chen fears chaining Wealth.
又：魁罡四柱日多同，贵气朝来在此中，日主独逢冲克重，财官显露祸无穷。
Also: GuiKang for 4 pillars are largely the same. The noble Qi comes from within, if DM sees heavy counters and clashes, or prominent and exposed Wealth and Officer, disaster is immeasurable.
按此格，俱用辰戌，独天干少异，戊庚辰二日，既曰日德，又曰魁罡，论其格局，迥然不同，不必拘论。
For this structure, all use Chen and Xu, as the HS is less different, the day of Xu Chen and Geng Chen, is called Day Virtue, but it is also GuiKang, and to analyze these structures are very different, thus one does not have to be inflexible when analyzing.
如张时佥事：
Like (the chart of) Zhang (some titles)
庚午、丁亥、戊戌、丙辰；
Bing Wu Ding Geng
Chen Xu Hai Wu
刘大受少卿：
(the chart of) Liu (some titles)
丁亥、癸丑、庚戌、戊寅，
Wu Geng Gui Ding
Yin Xu Chou Hai
二命魁罡日，只取财官印是也。
These 2 are GuiKang day, but is only analyzed as Wealth / Officer / Seal.
Like all the classics, SMTH prioritizes the Month Command over an external structure.
庚午、丁亥、戊戌、丙辰；
Bing Wu Ding Geng
Chen Xu Hai Wu
Bing Wu Ding Geng
Chen Xu Hai Wu
Wu born in Hai is Wealth / Officer structure. Ding and Bing are Seals, so this is regarded as Wealth / Officer / Seal
丁亥、癸丑、庚戌、戊寅，
Wu Geng Gui Ding
Yin Xu Chou Hai
Wu Geng Gui Ding
Yin Xu Chou Hai
Geng born in Chou with Hurting Officer and Seal protruding. So this is a ShangGuan PeiYin chart.
Trey: The classics are not unanimous when it comes to GuiKang structure. ZPZQ and SFTK say GuiKang structure do not exists. That is understandable from classical point of view as the Month EB is prioritized over all external structures.
There are some rules for a GuiKang chart to be established:
1. DayMaster has to be one of the 4 days.
2. Month EB has no use.
3. Wealth and Officer / 7K are not present
4. The chart does not transform nor follow.
Since there are about 500,000 BaZi charts and 15% of them are made of GuiKang DM, it's difficult to say if some of the 75,000 charts will satisfy all the criteria above. Probably GuiKang chart exists, but it must be really rare.
