Isn’t that episode called “Thirty Minutes Over Tokyo”?
A thought as to what this blackboard means (there’s a discussion about this at the website I have this comment linked to): after several episodes in Seasons 5-9 and early 10 where he didn’t write on the blackboard, with this one, he had written on the blackboard in 19 consecutive episodes. (Before this, the last time he had done so was a streak that lasted from “Itchy & Scratchy: The Movie” through “Cape Feare”: exactly 19 episodes, almost six years earlier.) This streak was left completely intact in syndication, as well.
Trivia: With the exception of three Halloween Specials, EVERY SINGLE ONE of the episodes with production codes starting with AABF, BABF and CABF use not only a blackboard but the full-length opening! According to DVD commentaries, this initiative was led by then-showrunner Mike Scully, who did this so that when they went into syndication, they could just cut the opening and leave the rest of the episode relatively untouched. (They _never_ cut the opening for Season 10, but they _always_ did for Seasons 11 and 12 (in fact, some of those episodes had to be _expanded_ because they cut too much), and they didn’t have to expand any of Season 13′s CABFs, but they _did_ remove all the SFX in their shortened openings up to the couch gag for some reason. The lesson: you can never trust the syndicators.)
I was afraid I’d gotten my math wrong… actually, it was 20 consecutive episodes. (The third episode of Season 10, “Bart the Mother”, did not use a blackboard; every subsequent episode through this one, the 23rd of the season, used one.) Note that, by production order within the season (which is how many stations show episodes in syndication), it is 19 consecutive (AABF01-18 and this one, AABF20; AABF19 was held over to Season 11, and the other episode in the 20-consecutive streak was 5F19). “Bart the Mother” (5F22) is the episode before the streak in both instances; there are episodes with 5F23 and 5F24 codes, but they aired in Season 9. (20th Century Fox shows all use the same style of production code; they changed the style of it during the 1997-98 season, but most shows (including “The Simpsons”) weren’t affected until 1998-99.)
In 5F22, the “5″ refers to the 1997-98 season for which it was produced, the “F” refers to the show itself, and the “22″ refers to the order in which it was produced for this season. (Note that the latter is not always consecutive; for example, there are episodes with 2F31, 2F32 and 2F33 codes, but nothing between them and 2F22. Even the “F” isn’t always consistent; there are “7G” and “3G” episodes, although 7G was part of an even older style of production code.)
In AABF01, the “A” refers to the fact that it was produced for the show’s tenth season (1 through 9 are used for the first nine seasons, although the switch in production code styles did not occur until “The Simpsons” was in its tenth), the “ABF” refers to the show itself, and the “01″ refers to the same thing it did in the previous code style.