ENFP and INFJ is the pairing MBTI communities call golden. The two share no cognitive functions at all, which is exactly why it works and exactly where it fails.
INFJ and INTP share two functions in inverted positions. That inversion is exactly why a logical INFJ and a warm INTP can each look like the other type.
INFP and INTP share their second and third functions, so both are curious, private and hard to pin down. The split is whether the inner compass runs on values or on logic.
ISTP and INTP both lead with Introverted Thinking, the same precise internal logic. One aims it at the physical world in front of them, the other at abstract possibility.
ENFP and ENTP both lead with Extraverted Intuition, so both generate ideas endlessly. The difference is what filters them: personal values or internal logic.
ISTJ and ISFJ are the two most common introverted types and together account for a quarter of the population. Both lead with Introverted Sensing. The split is what the reliability serves.
ISFJ is the most common type at 13.8%. INFJ is the rarest at 1.5%. They share their middle two functions, and the mistype runs overwhelmingly in one direction.
INTJ and ENTJ run the same four cognitive functions in a different order. One sees the endpoint then organises toward it. The other organises first and sharpens the vision as it goes.
INFP and ENFP run exactly the same four cognitive functions in a different order. That is why the pair is so hard to separate, and why sociability is the worst possible test.
INFJ and INTJ are the rare pair that share a dominant function. Both lead with Introverted Intuition. What separates them is what the insight gets aimed at: people or systems.
