In Vedic astrology the planets have different relationship with each other. They are either friendly, enemy, or neutral to each other. Here are relationship between planets as described by the ancient books. This is natural relationship of planets, apart from this, in astrology, there are immediate friendship, immediate enmity, and immediate neutral relationship among planets. The relationship is not necessarily reciprocal, for example, Moon treats Mercury as a friend but Mercury treats Moon as enemy. While analyzing the kundli it is important to keep in mind these planet relationship as suggested below.
Planets also have friendly, enemy and neutral relationship with zodiac signs.
Sun – Sun is friendly in Scorpio, Sagittarius and Pisces. Enemy in Taurus, Capricorn and Aquarius. Neutral in Gemini, Cancer and Virgo.
Moon – Moon is friendly in Gemini, Leo and Virgo. Enemy in no signs. Neutral in Aries, Libra, Sagittarius, Capricorn, Aquarius and Pisces.
Mars – Mars is friendly in Leo, Sagittarius and Pisces. Enemy in Gemini and Virgo. Neutral in Taurus,Libra and Aquarius.
Mercury – Mercury is friendly in Taurus, Leo and Libra. Enemy in Cancer only. Neutral in Aries, Scorpio, Capricorn and Aquarius.
Jupiter – Jupiter is friendly in Aries, Leo, Virgo and Scorpio. Enemy in Taurus, Gemini and Libra. Neutral in Aquarius.
Venus – Venus is friendly in Gemini, Sagittarius, Capricorn and Aquarius. Enemy in Cancer and Leo. Neutral in Aries and Scorpio.
Saturn – Saturn is friendly in Taurus, Gemini and Virgo. Enemy in Cancer, Leo and Scorpio. Neutral in Sagittarius and Pisces.
Rahu/Ketu – Rahu/Ketu is friendly in Gemini, Virgo, Libra, Sagittarius, Capricorn and Pisces. Enemy in Aries, Cancer, Leo and Aquarius. Neutral in nowhere.