https://www.edition-margaux.com/en/de/sonata-ii
The transition begins at measure 16 (00:44) and ends at measure 27 (01:10). If you're already familiar with Koshkin there's not much to say about this particularly but I suppose I might want to mention that in guitar sonatas there's a long tradition of having transitions that are more active than the themes in terms of rhythm and figuration. Koshkin's transition bursts forth with a super-expanded range of notes and sixteenth note riffs but it slowly and steadily winds down. Someone like Matiegka would have a flashy and buoyant transition that built UP to the arrival of a paradoxically lyric theme (Grand Sonata I, which I've discussed elsewhere back in 2015 and later in 2016 and along the way I had a full score of the first movement of GS I). A more through discussion of that sonata is something I want to do later this year drawing on earlier work. Before I get side-tracked further, the busy transition leading to a lyric second theme is a trope in guitar music and it's not a bad thing. Koshkin has given us a lively 12-bar blues for theme 1 and a spritely transition that winds down to the arrival of Theme 2 at measure 28.
Theme 2 is a lyric, melancholy theme in G minor (basically) played with tremolo from measures 28 through 48 (01:11 to 02:17). The contrast between the compact and aggressive first theme and this lyric second theme could not be starker in terms of mood. In that sense it's "textbook" but something that textbook explications of thematic contrasts in sonatas can leave out is that the "punctuation" of first and second themes can be different (and should be according to 18th century aesthetics and treatises on form but I'm hoping to save a discussion of Journeys through Galant Expositions for later).
The main thing is that there's something about how Theme 2 is presented that presents a structural contrast to Theme 1. If we're talking about a monothematic sonata form the distinctions could be simple but they need to be blunt. Was theme 1 in minor? Theme 2 can be theme 1 in parallel major. Was theme 1 on top? Bring back theme 1 as "theme 2" in a lower voice and change the accompanying figuration. You can have a stringently single-themed sonata provided you highlight contrasts around that idea. That's not what Koshkin did here, of course, he had a dramatically contrasting second theme that is melancholy and expansive as a contrast to the brisk blues.
He also has his second theme in G minor rather than the "usual" F major or A minor or A major. In "textbook" sonata forms if you start in D minor you would supposedly need to go to one of those three mentioned keys. But in the 21st century key contrast is not as important. Angelo Gilardino's late 20th century guitar sonatas don't use key contrasts at all. Gilardino relied on thematic contrasts in terms of character and phrasing to ... wait ... let me stop myself from going down that path because I'm trying to point out that one of the reasons Hepokoski and Darcy's Elements works so well is that even if they developed the idea to explain 18th century sonatas you can draw on those ideas to discuss even 21st century sonatas. If the rhetoric and structure of thematic progressions is retained (i.e. Theme 1, Theme 2, Theme 3 then Theme 1, Theme 2 and Theme 3 and Theme 1 ... ) then the memory of your listener is primed to hear the "rotation" of the order of the themes regardless of whether the tonal or pitch zones fit "textbook" sonata forms. Mnemonic devices such as "rotation" can work whether or not you obey "the rules" that were post hoc formulated by 19th century theorists.
So we've got this established. First theme (D minor) is a blues with a spunky transition that steadily and progressively winds down to allow for the arrival of a lyric, somber G minor theme with tremolo to bring out the long sustained notes of the melody). A second transition goes from measures 49 to 51 (02:17 to 02:28). This transition is a burst of ideas from the first transition that briefly seems to threaten that we're going to go into a development. Nope, this is a feint, and it leads to Theme 3 at measure 52.
Theme 3 goes from measures 52 to the first half of measure 59. This is a chorale in G minor and it's a three-phrase theme built on, this might surprise you, one of the barest bones tropes in all of guitar music, the Andalusian cadence. It's G, F, E flat and D in the bass, followed by D, C, B flat and A, which is followed by a reprise of the former lick. The gentle but bleak melody up drops down to D natural to outline a triad that lands on the fifth of G minor just when the bass and harmony hit E flat, which creates a penultimate harmony in the phrase of E flat major seventh, but if you have ears to hear, there's no denying this is an Andalusian cadence-based Theme 3. It's also short. By 03:00 in (second half of measure 59, roughly) Koshkin is subjecting Theme 3 to ornamental development that reaches a firm cadence in G minor at measure 68 (03:27). I've mentioned this as something that happened in Beethoven's Op. 111 piano sonata, but some composers shift the weight of thematic development to zones outside the development. Koshkin doesn't have a particularly big development section in this opening sonata form but he doesn't need one because he's put developing variations on his three themes inside the exposition and recapitulation zones.
So a development here can be proportionally small (and not explicitly marked out in the score by a double bar-line signal since Koshkin favors what Hepokoski might call a "continuous" exposition that has no real "medial caesura". The development, as I see it and hear it, is a tiny stretch from measures 68-85! There are hints and allusions to Theme 1 and scraps of Theme 3 but the development here is kind of a big build up passage that gets us back to Theme 1 and is not the kind of development that theory teachers in undergrad courses would ever pick as an example of "this is how you do it". But there it is.
The recapitulation of Theme 1 runs from measures 86 to 98 (04:19 to 04:49) and Koshkin's opening blues theme has returned. Only this time it's not even blues. Koshkin has dramatically revised Theme 1 and develops it in new ways within the recapitulation zone. The simplicity of the 12-bar blues realization of the idea is thrown aside and Koshkin develops a call and response contrapuntal variation on his material. There is also no "retransition". Remember how I mentioned there was a "turn-around" in Theme 1 in the exposition? Here there is no transition and Theme 1 is recomposed so that it resolves seamlessly into the return of Theme 2, which shows up at measure 99 and is now in D minor (04:51).
Theme 2 runs from measures 99 to 117 (04:51 to 05:50) and leads into the return of Theme 3 which is now in D minor. Theme 3 runs from measures 118 to 124 (05:51 to 06:18) in the recapitulation. Given that in its expositional form Theme 3 was such a skeletal Andalusian cadential peroration, and so short, you might wonder what Koshkin would do with it now? Will he present it as starkly as he did in the exposition? No, he has a little surprise here, which is that as each phrase of Theme 3 ends there are commentaries in an inner voice evoking riffs from Theme 1. Here, too, he's continuously recomposing and extending his material in the recapitulation rather than having done much with it in the development section. I hope by now you have seen and heard why I have made a point of comparing how Koshkin plays with his material in his opening sonata form with how Beethoven played with his material in his last piano sonata, both composers shifting the weight of developmental processes into the expositional and recapitulational regions of their sonata forms and away from what would be the "expected" development section in the middle.
Measures 125 to 134 (06:19 to 07:07) brings back the pulsing block chord motif from the development section as a kind of "theme 4" that rounds things off. Hepokoski and Darcy might call this a big double rotation sonata form that hews to Type 3 structuring, at the risk of laying out contemporary formal analytical theories. In Elements of Sonata Theory Hepokoski and Darcy explain that what a rotation is is a sequence of themes that are presented in a specific order. Themes 1, 2 and 3 are presented in sequence. If themes 1 through 3 are presented sequentially in a development section or two of the three themes, that can count as another "rotation", more or less. If Themes 1 through 3 come back in the recapitulation zone, however much changed, that counts as a second rotation. If themes 2 and 3 come back but not Theme 1 (here I'm thinking specifically of Simon Molitor's Op.7 guitar sonata) then the rotation is incomplete and this is where and why Hepokoski and Darcy call something a Type 2 sonata that doesn't have a recapitulation because it doesn't have the proverbial "double return". Koshkin's sonata form, however, does have a double return.
Not all sonata forms have it but many of them do. I want to digress into Yoel Greenberg's How Sonata Forms here but I'm trying to resist the temptation to rabbit trail into a bunch of books I've read or been reading. Still, Greenberg's book is new and a big part of his "bottom up" approach to analyzing forms involves pointing out three different elements that can show up in sonatas and how not all of them show up across all examples. We should not expect every sonata form to have a "double return", whether because Theme 1 doesn't come back at all or because it comes back in a strange way. I'm going to keep on this rabbit trail by reference to my past writing on these kinds of things.
A warped "double return" is when Theme 1 doesn't come back in the key in which it first appeared. Theme 1 may come back in a recapitulation but come back in an ostentatiously wrong key. Wenzel Matiegka did this in his funny Op. 31 No. 1 sonata in C major by having Theme 1 start in C major in the exposition but it shows up in A major in the recapitulation and modally mutates into A minor before finally only recapitulating "properly" in C major in the second half of theme 1. The absence of a "double return" doesn't mean there has been no recapitulation and this is where I simply differ with Hepokoski and Darcy. But where I find their theory useful, I use it, and the idea of double rotation to describe what has happened in the first movement of Koshkin's Guitar Sonata No. II is useful indeed!
Theme 2 (08:27 to 09:10) C major [episode]
Theme 1b (09:11 to 10:00) A minor [refrain]
Theme 3 (10:01 to 11:28) E minor [episode]
Theme 1c (11:29 to 13:24) A minor [refrain/coda]