This is a nice live performance of the whole set - something very rarely attempted. Many players won't even play one live, let alone the whole lot. You can tell that Tatsuki warms up into the set as it goes along so that by the time he is up to the 5th he is at full throttle with the engine temps all in the green zone!
It is interesting to note that in the first Caprice Paganini's original bowing directives (sympathetically reproduced in the very-long standing International Music Ivan Galamian edition with a notoriously blood-red coloured cover as an ominous warning of what lies within the pages) required an even more advanced technique than is used by all players that I know of - at least in the last four decades or so, with the rare exception being Itzhak Perlman (who of course was a Galamian pupil himself). The reason being is that these works are hard enough as it is and to manage them with the original intended bowings puts it into the realm of the near-impossible. Paganini never wrote these so that players on every street corner could enjoy them. He wrote them because he knew it would demonstrate his vast technical superiority over everyone else.
In that first Caprice the descending thirds are actually notated as ricochet bowing - not spiccato. With the ricochet bowing, the whole descending scale would be played with a staccato effect with the bow bouncing off the strings between each chord, but crucially the bow is only pulled in the down-bow direction when doing so. The bow thus bounces on and off the string in the one direction as opposed to what everyone does these days which is to alternate between up and down bow for each chord (spiccato). But you will have a lot of trouble finding
any videos of anyone doing the ricochet. I could not find any at all which to me says how difficult Paganini
really wanted these pieces to be. I think he honestly wanted them to be so difficult that no one apart from himself could ever get up in front of an audience and pull them off the way he annotated them.
But in the 5th Caprice, the semi-quavers are also notated by Paganini himself to be played with the first three of each group of four as ricochet and the fourth one a single "recovery" up-bow! That is incredibly difficult since there is only a limited part of the bow that is amenable to ricochet in the first place (tending to be the around the middle upwards) yet you only have one single note (played at an extremely fast tempo) to get that bow back up to that point form the next group of 4! So as if it were not hard enough as it is, you get one quarter the amount of time you had for the ricochet to get the bow back to where it was!
And I am happy to report that in this performance Tatsuki bites the bullet and does it the hard way as described above. It is virtually impossible to do this as cleanly as the "cheater's" way out which is to employ sautille bowing (well even that is actually extremely difficult as well since you are playing very fast with string crossings).
It you want to compare the two ways of doing it - watch Tatsuki play the 5th then look at Antal Zalai's video here:
https://youtu.be/V0otZkH4VuM?t=997
you will see that Zalai choses a more moderate tempo and in combination with the sautille it sounds cleaner but it is significantly less dramatic. But it is the performer's choice - elect to be faithful to the original edition like Tasuki does where it is inevitably going to sound a bit more grungy yet spectacular versus the "safe" and "clean" sautille approach that almost everyone uses except the really great players.
Another interesting thing to observe in this performance is the spontaneous loss of bow-hair after the 14th Caprice. This is not Tatsuki's "fault" - this Caprice is a bow and bow-hair killer as you are asking the bow and bow hair to accomplish something that almost defies physics - playing 4 strings at once with a modern bow on a curved bridge. It needs a massive amount of practice to do this cleanly and when I finally learned that piece my bow had probably lost about 10% of it's hair! It think it is quite funny watching him pull the broken bits out actually since I think every player who has ever played this can relate to it!
One other interesting note: Paganini apparently had pretty large hands but even hand size is just one attribute needed to navigate these pieces. The stretches required are insane on a full-sized instrument, especially playing in tenths. My teacher was a Galamian pupil and she mentioned to me once that she got tenosynovitis when she was made to learn them! She had pretty tiny hands - I don't think it was fair to be honest. It was like making the women compete with the men in the Olympic Basketball!!