Now, what does it mean to have 6th house lord sitting in 12th house?

It means the planet which rules/controls/owns the 6th house of your horoscope is sitting in the 12th house.

Now, what is the impact of having 6th house lord sitting in 12th house?

Its generic interpretation is that your daily life routine is going into the matters of 12th house. That means either you are working at a Foreign Lands or in MNC etc. It shows you may be aDoctor or a Warden or Caretaker in Asylum. It also shows Spiritual thinking is huge part of your daily routine. As 12th house is house of losses, it shows there is no great expectations of results with actions you take. You consider it as your Spiritual Duty and submit your actions to the divinity. It doesn't mean they are not ambitious because there will always be other planetary placements.

Now, results may be different due to aspect, conjunctions of other planets or the planet being Retrograde or Combust. Moreover, now we also need to check the strength of 12th house lord as 6th house lord is going in 12th house. So again, Overall Chart Reading is important.

So, let's see how different planets will behave differently as 6th house Lord in 12th house.

Sun - Suppose it is a Pisces Ascendant chart and Sun rules the 6th house with Leo sign and sits in 12th house in Aquarius. It shows someone working in isolation or foreign lands in large organisations. It can also show someone working in Scientific or Medical Field where they are in continuous research on medicines. There is a generic phrase about Sun in 12th house that Sun goes in 12th house to Die. It means these people have hard time finding their pride and confidence as it is thrashes by either abuse of Father or absence of Father. This also becomes the reason of their moving into isolated places. Big part of their life goes in regaining that lost confidence, but with hard work in 6th house matters and spirituality of 12th house, they get it.

Moon - So it is Aquarius Ascendant Chart and Moon rules the 6th house with Cancer sign and sits in 12th house in Capricorn Sign. It shows a person who is into health care field as a Doctor or Nurse. They work in Foreign Lands as Caregiver or a Healing Professional in any Hospital. As Moon is in Saturn's sign, it shows that person will get success after hard work only and person feels lack of nourishment from Mother. May be Mother was herself a very hard working and career oriented lady who kept on travelling and stayed away from the native.

Mars - Mars can be 6th house ruler through its two signs. So, let's take both one after the other.

Scorpio Ascendant - So if it is Scorpio Ascendant, Mars rules 6th & 1st house and sits in 12th house in Libra. This shows that person may be a healer who works in hospital and has a motivating outlook towards healthcare. It means they will energize their patients with a pep-talk before they give any medicine. They can also be a sportsperson who travels to a foreign lands to caompete and win laurels to country. They can even be seen as Warden or Jailers in a Jail. As Mars, a natural malefic planet, is not in a very good dignity here and 12th house is also a house of escapism & addictions, if there are further malefic influences on this Mars, it shows someone getting into Drugs and landing in to Jail.

Gemini Ascendant - Now if it is Gemini Ascendant, Mars rules 6th & 11th house and sits in 12th house in Taurus sign. This is a very similar situation as Mars is in Venus ruled sign again. So, we can see similar results here. Additionally, this person can be a Surgeon as Scorpio is sign of Surgery and 12th house is hospitals. It also shows person has great amount of wealth in foreign lands or places associated with 12th house, as Taurus is the sign of Wealth. So, efforts and actions of Mars are directed towards gaining wealth and assets.

Mercury - Mercury also can be 6th house ruler through its two signs. So, let's take both one after the other.

Capricorn Ascendant - If it is Capricorn Ascendant, Mercury rules 6th & 9th houses and sits in 12th house in Sagittarius. Mercury is Collection of knowledge & Communication/Counselling, Sagittarius is sign of Preaching and different religions/philosophies, 6th house is obstacles and 12th house is spirituality and spiritual places. Indications are very clear. This person will be very curious to learn about different religions and philosophies of the world. Later in life, he will preach/communicate and counsel people through the same philosophies as to how they can overcome their obstacles. Mercury or Venus in Sagittarius people are normally voracious readers.

Aries Ascendant - If it is Aries Ascendant, then Mercury rules 6th & 3rd house and sits in 12th house in Pisces, where it is debilitated. This changes things a little bit but not much. Instead of Religion and Philosophy, they love teaching and preaching about Spiritual Values and how people can remove obstacles through Spirituality. Here, imagination goes for a real high leap and then they use that imagination in their writings. So, actually some best selling authors are seen with debilitated Mercury.

Venus - Venus also can be 6th house ruler through its two signs. So, let's take both one after the other.

Sagittarius Ascendant - If it is Sagittarius Ascendant, Venus rules 6th & 11th house and sits in 12th house in Scorpio sign. Venus in Scorpio clearly shows some karmic backlog related with relationships. Although, they may love to serve and heal people who are sick and unhealthy, but their personal relations will be going through turmoil. This position shows some abusive relations in early life and transformation in relations. They love the occult side of world and discussion about occult matters. A guy may marry a girl from Foreign Lands.

Taurus Ascendant - If it is Taurus Ascendant, Venus rules 6th & 1st house and sits in 12th house in Aries. Although, situation is not as bad as it was in earlier position but still Venus is in Mars ruled sign. So, it shows an aggressive relationship. It means couple would be having aggressive talks and arguments every now and then. There remains a chance of physical abuse or substance abuse in relationship. Chances of marrying a Foreigner remains there. Couple would assert their individuality, means they won't want any interference in their life.

Jupiter - Jupiter also can be 6th house ruler through its two signs. So, let's take both one after the other.

Cancer Ascendant - If it is Cancer Ascendant, Jupiter rules 6th & 9th house and sits in 12th house in Gemini Sign. Clearly a Preacher as Jupiter is in 12th house of Spirituality and in the sign of Gemini which is all about communications. So, these people would preach public on spiritual and religious matters and help people remove their obstacles in life. This time, a girl has good chances of meeting her husband in Foreign Lands. Again, they have huge collection of spiritual and religious information. They may travel to different countries to impart their spiritual knowledge.

Libra Ascendant - If it is Libra Ascendant, Jupiter rules 3rd & 6th house and sits in 12th house in Virgo. This person becomes quite an analyst regarding religion and spiritual beliefs. Give them 100 books on different religions and philosophies, they will read all of them and then they will write a new book in which they will thrash every fault of every religion and philosophy :). Alternatively, they can be working in MNC in the field of Finance and more appropriately as an accountant and analyse the numbers. Foreign spouse chances are there for a Girl.

Saturn - Saturn also can be 6th house ruler through its two signs.

In either sign (Capricorn/Aquarius) as 6th house lord, Saturn in 12th house (for Leo/Virgo Ascendants respectively) shows that access to foreign lands or foreign travels came late in life. In early life, they may have tried a lot to reach to foreign lands but their may be one or the other obstacles. It also shows someone in Service of others in Foreign Lands, most probably in MNCs. Saturn in Leo for a Virgo ascendant may show troublesome relations with father. It also shows that person is frugal or miser and doesn't spend a lot. Saturn in Cancer for Leo Ascendant shows a healer and someone who has some issues running with mother. It also shows a Lawyer or Judge in Foreign Lands.

Rahu - If Rahu is 6th house Lord through its sign Aquarius, as it co-rules Aquarius along with Saturn, and sits in 12th house in Leo then 1st of all we need to make sure of Saturn's position as it is the main ruler. Rahu in Leo in 12th house will transform Rahu as Sun as Rahu changes its nature as per the lord of sign it is placed in. So, it will become much like Sun in 12th house as discussed above but at the same time, Rahu's basic nature of being insatiable will remain there. Rahu in Leo in 12th house shows a person who is kind of power and fame hungry. They can do anything to become a known person. Now, it depends on Sun's position that they will do good or bad act. At the same time, Rahu is also the one which castes its dark shadow over Leo. So, they want fame but they are afraid to go on stage. This tug of war continues till mid 30s. Their fame comes from foreign lands. They can be kind of spendthrifts.

Ketu - Likewise, If Ketu is 6th house Lord through its sign Scorpio, as it co-rules Scorpio along with Mars, and sits in 12th house in Taurus then 1st of all we need to make sure of Mars' position as it is the main ruler. As Ketu isolates/separates a person from the things related to the house Ketu is sitting, here it separates person from the spiritual beliefs spread by others. They never find themselves agree with the concepts of spirituality of others and always find fault there. Similarly, they reach foreign land but don't find anything of interest there and feel isolated. It is one of the most prominent Moksha Margi position. Ketu in Taurusshows that these people are not much into hoarding wealth and hence it comes easily to them.