Early evidence suggests much more than a single intruder event over Sakhalin. Whilst the US government struggled to release any information at all, the Hokkaido Shimbun managed to get and publish radar traces from Wakkanai on Sept 1st in their 2pm edition, less than 8 hrs after incident. The map was also published the following day in the Ashahi Shimbun.
Hokkaido Shimbun radar track and text clearly state the track of KAL007 passing directly over Dolinsk and exiting over Gornozavodsk. The map shows KAL007 disappearing from radar at 3:28 Japan time (UTC 16:28) and Soviet interceptors scrambling much later at 3:53 and also in another area at 3:32. The KAL007 track is dead straight.
However, 7 hrs later at 9:30pm Sept 1st the Japanese Defence Agency (JDA) published a radar map that is very different.
The JDA radar track is curved and exits above Kholmsk, nearly 50km north of where the newspaper reported the plane exiting Sakhalin. In order to compare the maps, both were georeferenced using mapwarper.net then overlaid. So it appears there were at least two intruders over Sakhalin. JDA later clarified this map was produced “based on radar records processed comprehensively at the Misawa Air Defense Control Center, and does not show the detection status at each radar”
There is still more ambiguity in the JDA map and clearly shows some information is withheld.
The Soviet interceptor “B” can be seen on radar at a much greater distance than the much larger 747-200. In Iwao Koyama’s book “The Missing Bodies” he shows the Wakkanai radar easily detecting a low level search performed at a much greater distance the following year. David Pearson with his research states that Wakkani radar at the time was a proven 250 miles (402Km) and theoretical 300 miles. It appears the track of KAL007 prior to 3:12 is withheld, possibly because it shows a turn as reported by the Soviets.