I have to say that the "yield rate" of truly outstanding performances among Asahina's numerous Bruckner recordings is relatively low. However, it is not to say that his Bruckner is mediocre. In fact his Bruckner has invariably been, with few exceptions, able to impress. I have attended only one of his Bruckner concerts, in Osaka in Februrary 2001, ten months before his death. This Bruckner's 8th was a very good performance, but it ultimately lacked the kind of incandescence and inevitability of Wand. To be fair, it was much better than many Bruckner concerts that I've attended, however.
What is unique about his Bruckner is the high degree of transparency despite a sound picture with emphasis on the basses. Small details in the score will thus be revealed to the attentive listener. Here he bears a not too remote resemblance to Celibidache. He is able to sustain long lines with a generally broad tempo, but I was rather disturbed by his sometimes hurried and seemingly impatient phrases within a part of a movement.
Among his recordings (I suspect that I've collected all), Bruckner's 5th and 8th were considered his specialties in Japan, and I tend to agree. His Bruckner's 4th and 7th were not particularly brilliant, at least when compared with those venerable Brucknerian giants. His Bruckner's 9th is sort of a special case.
In general, his recordings can be more easily classified according to the record label. The Jean-Jean set shows a budding Brucknerian in a provincial orchestra, the Osaka Philharmonic founded by Asahina in 1947 when it was first known as the Kansai Symphony Orchestra and later changed to the present name in 1960. The JVC set involves many different orchestras and shows signs of improvement. The full Pony Canyon set featuring the Osaka Philharmonic recorded in the 1990's reaches the peak of his Bruckner performances with some prime recommendations among his huge discography. There is also a partial set issued by Pony Canyon (with Tokyo Symphony Orchestra) but it does not surpass the full set. Fontec issued different series of his cooperation with mainly three orchestras: New Japan Philharmonic, Tokyo Metropolitan SO and NHK SO. The 3 discs with NHK SO show very focused playing with excellent ensemble and acoustics. The discs with the other 2 orchestras are OK, but there is one excellent 7th with TMSO. Exton presents live recordings of his Osaka Philharmonic concerts in the last years of his life, with generally gorgeous sound, but regrettably also shows his art in decline.
Here are my comments on individual symphonies:
4th: Not his strong point. Either NHKSO (2000, Fontec) or Osaka PO (2000, Exton) is good if you want to hear his Bruckner's 4th.
5th: His Osaka PO performance for his 90th birthyear (1998, Mainichi) is a memorable experience. Another good one is with the Tokyo Symphony Orchestra (1995, Pony Canyon) in the small boxset.
7th: Many Japanese critics were very enthusiastic about the concert at St. Florian in 1975 (JVC single disc) with the church bell unexpectedly sounding right after the Adagio. There is a spiritual quality to this performance but the playing is not tiptop in his case. A surprisingly nice recording is the one with Tokyo Metropolitan (2001, Fontec), with very natural flow and smooth sonority.
8th: Asahina has always used the Haas edition. Some may prefer his last recording (July 2001, Exton), but I'm concerned with some clumsiness here and there, and at times the Adagio even sounds somewhat stolid. The earlier performance that year (Feb 2001, Exton) is better. It was recorded in Nagoya three days after the concert I attended in Osaka. The pianissimo was exquisite and the long lines were held solidly. The NHKSO disc (1997, Fontec) is good in its own right. But if I have to choose only one disc to represent Asahina's Bruckner, it'd be the 1994 recording with "his" orchestra, the Osaka Philharmonic (Pony Canyon). It show him in his best light, in the prime of his Bruckner career.
9th: Again the 1995 Pony Canyon (Osaka PO) is preferred among his many recordings, an expressive yet not oversentimentalized interpretation. His very last Bruckner recording on Exton can only be recommended for sentimental reasons, it being let down by what I'd call a "disjointed poignancy".
People of course will differ in their opinion, and so I welcome comments from you.