Raff's music was well known to Tchaikovsky, although there is no record of the two men ever having met. Whilst apparently the most civil of people in conversation, the russian's views on his contemporaries in print were often uncompromising and frequently uncomplimentary.
In his private writings, Tchaikovsky was especially critical of Brahms, whom he called a "scoundrel". In a diary entry of 1886, four years after Raff's death, he wrote about Brahms: "What an ungifted swine! It angers me that this conceited mediocrity is regarded as a genius. Why, in comparison with him Raff is a giant, not to mention Rubinstein, who, when all is said and done, still is an outstanding and living human being. Whereas that Brahms is just some chaotic and utterly empty wasteland". In a letter to his patron Nadezhda von Meck he commented on a letter he had received from the famous conductor and pianist Hans von Bülow, a lifelong friend of Raff's: "he told me that in his view there were five composers on whose shoulders rested the future of music, and these five were the following: Raff, Brahms, Saint-Saëns, Rheinberger, and me. It was very flattering to find myself in the company of the first three, but being put next to Rheinberger—that really astonished me! What could he possibly have found in Rheinberger's music? I am not a great fan of Raff or Brahms (indeed I do not like the latter at all; I just respect him), or even of Saint-Saëns, but still these are big shots, whereas Rheinberger is an absolute nonentity."
It seems clear that, although he was by no means an uncritical enthusiast of Raff's music and clearly regarded him as no more than an expert craftsman, he did appreciate in particular the older man's structural and orchestration skills. It is quite common to hear a passage in an orchestral work by Raff which sounds "Tchaikovskian", although the piece was written well before any of Tchaikovsky's works would have been known in Germany. As Tchaikovsky makes clear, Raff was frequently played in Moscow and St Petersburg in the 1870s and 80s and it seems clear rather that there are elements of Tchaikovsky's works which sound "Raffian". The most striking example is in the slow movement of his Fifth Symphony, where the famous horn melody mirrors almost exactly the melodic outline and orchestration of a prominent passage in the slow movement of Raff's Tenth Symphony Zur Herbstzeit, written seven years earlier.
Early in his career, Tchaikovsky wrote musical criticism for Moscow magazines. For the Contemporary Chronicle he reviewed the first concert of the Russian Musical Society held on 5 November 1871 (Gregorian calendar), in which the violinist Ferdinand Laub was accompanied by an orchestra conducted by Tchaikovsky's friend and mentor Nikolai Rubinstein in a performance of Raff's konzertstuck La fée d’amour, which received a ringing endorsement from him:
"In this concert Mr Laub played a very interesting fantasy by Raff —La fée d’amour. Raff belongs to the most outstanding contemporary composers of the German school. His music does not display striking originality, he does not astonish the listener by exuberance of the creative faculties and imagination, but he is able to capture a sensitive connoisseur by the sophistication of his technical development and by his perfection of form. It is very remarkable that Raff has been able to preserve himself from the seductive influence of Mendelssohn, whose monotonously sentimental music has produced such an abundance of feeble imitators who endlessly repeat some of his typical stylistic devices, which have long ago become rather trite commonplaces.
"Raff displays a very close affinity with the Beethoven school, from which he has borrowed the noble simplicity of his themes, the logical thematic development of his ideas, and in particular artistic moderation in the choice of orchestral effects. A great deal of character and artistic commitment is required to refrain from the bombastic, awkward effects which modern composers are so liberal with. The second theme in the abovementioned piece is particularly charming. It is full of passionate languor and caressing tenderness. Mr Laub's interpretation was above all praise—Moscow has every right to be proud of having within its walls this Titan amongst violinists."
Just over a year later, the Russian Register printed a long review of Nikolai Rubinstein's performance of Raff's Symphony No.3 Im Walde at the Russian Musical Society's fifth symphony concert in Moscow on 13 December 1872: "The most important work on this concert's programme was Raff's Im Walde Symphony. I have already had occasion to point out the significance of this composer with regard to a string quartet of his which was performed at one of the Russian Musical Society's chamber music concerts, and now, with regard to his new symphony, which has attracted the attention of the whole musical world and is performed successfully in all the major music centres, I would like to discuss his career in more detail.
"Ever since death, with such untimely haste, struck down Mendelssohn and Schumann ... no creative talent has appeared yet in the field of symphonic music of whom one could say that he had begun a new artistic era ... among the now living composers there is not a single one who .. is not an imitator of one or the other—and often of both at the same time—of these two great symphonists of the modern age. ... There are only two symphonic composers in our times whom I could point to as standing out quite vividly against the greyish backcloth of modern music-making: they are Anton Rubinstein and Raff.
"The latter is considerably inferior to Rubinstein in terms of the strength and originality of his talent, but he does surpass him in technical craftsmanship, in the ability to achieve a wholeness of form and the working out of the constituent details. Raff has attained his high position amongst contemporary composers and secured success for his music through assiduous hard work and by vigorously fighting against his natural shortcomings, in particular the poverty of his inventive faculty. But what is there that cannot be achieved by earnest hard work?! Raff, by gradually perfecting his naturally limited gifts, has obtained brilliant results, and I am hardly mistaken in calling his latest symphony the finest of all the symphonies that have been written in the past decade. It is considerably better than another symphony by the same composer, entitled An das Vaterland, which is remarkable in some of its episodes but is altogether too long and uneven in form.
"In the first movement of his new symphony, which is meant to give a musical illustration of the various impressions one may have when walking through woodland, Raff attempts to convey the feelings that the quiet of a forest at midday can awaken in the wanderer. Both of the main themes of this Allegro are indeed pervaded by a sense of quiet, serene enjoyment of a peaceful forest landscape. The quietness is but fleetingly interrupted by the rustling of leaves as a gentle breeze sweeps through; from afar we vaguely hear the call of a shepherd's horn which is answered by some other distant calls from elsewhere, and then we are back again in the imperturbable quiet of the forest thicket… For the benefit of the specialists, I should like to point out the charming detail of how an orchestral pedal note effect is repeated several times in the treble clef, in both the tonic and the dominant, whereby the strings, gradually becoming quieter, modulate across various keys and finally fade away in the tonic triad.
"The second movement (Andante) is the best one in the whole symphony. It is based on a delightful cantilena which is splendidly harmonized and adorned with an incredibly felicitous instrumentation. A particularly enchanting effect is produced when the main melody appears for the last time in the violas and cellos, accompanied by the violins con sordino. This movement fully manages to convey the vague, sweet emotions which one feels at dusk amidst the darkness of a forest. The Scherzo is meant to illustrate a fantastic Dance of the Dryads. This movement went down especially well with the audience thanks to the spicy instrumentation that successfully camouflaged the rather wishy-washy themes, which were not at all original and even lacked the fantastic aura required of the composer for a scene of this kind.
"In the loud and striking Finale we are shown a wild hunt galloping through the forest with brilliant fanfares and cries of frenetic high spirits. The themes are not particularly novel, but characteristic all the same. Their development is most interesting, and the orchestration is colourful and accomplished. Then the hunting party vanishes in the distance, quietness descends again on the forest, and the rays of the rising sun drive away the darkness of night. The symphony closes with a triumphantly radiant theme, which is quite appropriately played by the four French horns and leaves the listeners with an impression of the mighty beauty of the bright daylight that is shining on eternally beautiful Nature."
Two years later, on 6 February 1875, Nikolai Rubinstein conducted Raff's Overture Ein feste Burg ist unser Gott and Tchaikovsky reviewed his performance for the Russian Register: "The overture by Raff with which the Russian Musical Society's eighth symphony concert opened is based on exactly the same theme of the Lutheran chorale which Meyerbeer made such effective use of in Les Huguenots. Luther's beautiful tune has been so splendidly elaborated in that opera, that it must have taken a great deal of courage and mastery to use this tune as a principal theme and illustrate it by means of polyphonic and orchestral development without falling into the trap of imitating such a master as Meyerbeer.
"Raff was able to cope successfully with this challenge. Apart from the chorale theme, his overture also makes use of two themes of his own invention, of which the second is not without freshness and originality. At the end he also availed himself of a little German folk-song, which is quite banal in its melodic contours but has a certain warlike ardour, and, thanks to a brilliant instrumentation and splendid harmonisation, it serves as a most effective conclusion to the overture. Raff's creative gift is by no means of the first rank, but he is endowed with expertise and technical skill, which can to some extent substitute for talent and inventiveness in his case. His works are smooth, coherent, adeptly structured in terms of form, and splendidly instrumented, as a result of which one listens to them, if not with a shudder of enthusiasm, then most certainly with great pleasure."
Raff's newly-composed Cello Concerto No.1 was played by Wilhelm Fitzenhagen at the Russian Musical Society's second symphony concert in Moscow on 26 November 1875, again under Nikolai Rubinstein's direction. Tchaikovsky wrote in the Russian Register: "The soloist that evening was Mr Fitzenhagen, who gave a very successful performance of Raff's concerto. ... like all of Raff's compositions it is intelligent and elegant, it shows an impeccable facture and is noble and beautiful from beginning to end. True, the themes are not particularly original, but in view of the shortage of works specifically for the cello this is not a flaw which we need lament too much. The fact alone that it gives the soloist a chance to unfold and exhibit the many-sided qualities of his virtuosity is in itself a sufficient recommendation for the work. The orchestration has been done very thoroughly and delicately, so that the solo instrument is not drowned out anywhere." He referred later in the same review to "Raff's interesting concerto."
Tchaikovsky was less enamoured of Raff's chamber works. In reviewing a performance of Brahms' String Sextet No.1 in 1872 he wrote: "The first-movement Allegro and the Finale are no different from what we find in works of this kind by such contemporary German composers as Bargiel, Raff , Rheinberger, Volkmann, and a whole phalanx of other artists who deserve respect for their splendid technique and earnestness of style, but who lack that spark of inspiration which would infuse their works with life and strength." He dismisses the String Quartet No.4 as "rather weak" and categorises Raff as belonging "to the same league of composers as Brahms". His final chamber music review was of another quartet, the String Quartet No.1, which was played by the Moscow Quartet on 7 November 1875. Tchaikovsky wrote in the Russian Register: "Raff's string quartet is exactly the opposite to Rubinstein's trio [his Piano Trio No.4]. Although he is no less prolific than the latter, Raff is by far the poorer in terms of ideas and imagination, even if he does considerably surpass his rival in the field of contemporary instrumental music with regard to the wholeness and perfection of his music's facture. In the quartet I am referring to here there is nothing outstanding, nothing that truly grips one, but on the other hand it does contain a lot of musical prettiness that can be accounted for by the wonderful technique, skilful calculation in the treatment of form and harmony, and especially by that know-how which the author has acquired in the course of many years of practice as a composer."
[This quotations from Tchaikovsky's letters and magazine reviews are all courtesy of www.tchaikovsky-research.net, an impressively comprehensive site dedicated to the promotion of Tchaikovsky's life and music]