Kalyan is the name of a raga which in later periods also became known as Yaman. According to tradition this raga is auspicious, it harmonises feelings, it brings joyfulness and happiness, improves mental and physical balance, chases away dark feelings and opens the heart and the mind. Because of its auspicious nature it is often taught to music students as the first raga, in spite of the fact that it is rather difficult to perform well.
First of all let us look at the tone material of Raga Kalyan. The notes it uses are the approximate equivalents of the Ancient Greek Hypodorian Mode or the later Lydian Mode. For the sake of easy notation we shall consider the note f to be the tonic. (Intervals in ragas are always measured from the tonic or base note, which also remains audible during a performance as a drone. Any note may serve as a tonic, since Indian Music does not recognise any fixed pitch.) Here is the tone material of Kalyan:
  
As we can see,  the fourth interval is e tritonus. Although the tritotnus forms part of the natural series of harmonics as the 11th overtone, it is an extremely difficult interval to come to terms with. In music theory there exist many kinds of warnings against its diabolical and enticing nature, and it became known as the "diabolus in musica" in Western musical tradition. (The Guidonian Doctrine of Solmisation, for instance, contains such a warning against Mi contra Fa,, diabolus in musica). The tritonus forms the delicate borderline between the two helves of the octave (exactly 1 1/2 in the case of equal temperament), yet, as many "central issues" it is often difficult to control end to come to terms with, a strange uneasiness about it remains. As late as 1951 the eminent musicologist Ernst Bindel in his work "Die Zahlengrundlagen der Musik" refers to the tritonus as a confuser or upsetter (Durcheinanderwerfer), "because it is a bastard interval from the illegal connection between the pure fifth and the fourth" ¹⁾. He sees the power of the great temptor (Versuchermacht) in this interval and speeks about our instinctive aversion to it. Hindsmith speaks of the tritonus in the following may: “The octave as the most distinguished and noble interval does not mix with the crows; the most distant relative, the freak, the half-genuine tritonus stays away  from the pair like Loki from the Gods - and yet - it is equally indispensable to them” ²⁾.
Many more examples could be quoted, but from the few remarks it is already evident that the tritonus seems to represent an aspect about which we simultaneously feel uncomfortable, curious, excited, afraid or insecure. Within our own nature it represents that which we do not have fully under control, our hidden non-compatible aspects, our repressions, aspects we would prefer not to have or try to hide, that which is not integrated.
Yet, if we succeed in integrating the just mentioned aspects, we become, more complete and therefore more harmonious than before, since a process of individuation has taken place. We shall then experience this diabolical interval as life-giving. Frightening spirits in fairy tales lose their threatening nature when called by their names. In fully recognising and controlling the tritonus in a raga we achieve mastery over the above mentioned darker aspects, this is the specific  "therapeutic programme" of Raga Kalyan.
How do we achieve this?
First of all by changing the perspective within the raga. To the previous scale we join another scale:
In this, the basic note f, our  tonic, is omitted, so is the fifth. The effect of this scale upon the impression of the previous is one of de-stabilisation or dissolution, a new relative aspect results while the nature of the tritonus is experienced from a different angle or rather against a different background.
But we are not aiming at a conversion of one scale into another here, because the tritonus must remain tritonus. Instead we are creating a kind of bi-tonality, in which the following kinds of melodic movements may emerge:

It is evident that in this case both the scales are used. Because of  the strong emphasis of the 7th (e), we gradually begin to hear this interval as a kind of substitute tonic or second tonic, not as a note leading to the next higher interval which is the actual and always audible tonic (or its octave). It is therefore essential that the musician first establishes the 7th as an important independent interval while developing the outline of the raga in a performance, since without a change in perspective the tritonus cannot be "tamed". It is equally important that he avoids a too early use of the fifth, since this would easily put the newly gained perspective in question because of its stabilising and fixed character.(Tonic and fifth are known as achala svaras, i.e. "fixed intervals" in Indian Classical Music.)
The more uncomfortable the listener feels about the tritonus, the more insistence upon the 7th will be required, since this is the only way to "melt down" the nature of the harshness of the tritonus and make it more acceptable. The nature of a musical introduction to that raga, which is always improvised and known as alapa, may therefore differ from one situation to another, for it depends upon the listener’s state of awareness and condition. The performer must be able to adjust to the situation from moment to moment. If the listener feels that the scale without tonic and fifth pulls the carpet away from under their feet because of its relativity, he will gently return to the tonic but not from the 7th, but rather via the sixth:
since the sequence
would put the previously established and accepted independent 7th in question.
Here lies this art of subtle musical alchemy. A particularly expressive interval in this raga is the third (a). In this interval the union between the two scales is experienced since is prominent in both scales. Known as the "speaker note" (vadi) in this raga, it suggests the integration and harmony we are aiming at. This effect is enhanced by providing it with the 7th as an "assistant speaking note" (Samvadi) as a constant companion.
In the case of intelligent use of both the scales, the tritonus is gradually transmuted into a perfectly compatible interval, it loses its dissonant and incompatible nature and becomes a life-giving and healing experience. (Observe the expression and movement of an audience after having listened to Kalyan!!) During the process of listening to this raga the listener gains control over his more hidden self, his repressions are gently released and integrated into the whole of his personality, complexes and tensions as well as fears are removed, they "have been called by their name", and the raga is experienced as therapeutic music in the true sense.
The effectiveness of the raga can be further enhanced by the suitable choice of a particular instrument or voice and a suitable rhythmic /metrical time cycle called tala. A tala is a modal form of rhythm/metre, which is effective because of :

• the overall number of time units it contains,
• The specific grouping of time units into groups,
• The accentuation of certain groups of time units within the tala.

Syncopation is often used, as well as polyrhythmic and polymetric variations. Thus the various levels of musical timing, one above the other, or rather within each other, are being created and the listener is simultaneously aware of time on different levels and with different qualities. This particular splitting of awareness brings the unconscious into the open, it has a liberating effect. Jazz musicians use this technique as well, hence the liberating effect of good jazz. The attempts to come to terms with the tritonus in jazz by musicians of the bebop style also has to be seen in this light, compare the eminent saxophonist Charlie Parker for instance. To round off the encounter with raga Kalyan we would like to describe an Indian miniature Painting representing this raga:

A gentleman and a lady in a garden stand close to each other or step towards each other. The lady offers a present to the gentleman which he is about to touch,  their eyes meet. Below exactly under this scene, a refreshing fountain is seen, and the dominant colour of the painting is green.

Schubert also described the nature of the tritonus as green. The painting speaks for itself.