Godzilla Raids Again (1955) a.k.a. Gigantis the Fire Monster
I found it very confusing as a kid when the monster was referred to in the English-language version as Gigantis. Apparently, it had something to do with copyright issues for the American distributors. Whatever the name, I personally consider this to be the all-time low of the Showa series, pretty ironic considering it was the first follow-up to the classic original. The problem here is that the series has not yet hit its stride. The movie lacks the depth and gravity of Gojira, yet it also lacks the fun vibe of the sequels to come. In short, it's a bore. The human storyline is a far, paper-thin cry from the gripping drama of its predecessor, and it features Akira Ifikube's least remarkable Godzilla score. On the positive side, the film introduces us to that wonderful giant armadillo Anguirus, and marks Godzilla's first on-screen battle with another monster.King Kong vs. Godzilla (1962)
For my money, this is when the Godzilla sequels really kick in. It's telling that there was a seven-year gap between Raids Again and this--perhaps Toho felt the need to go back to the drawing board and rethink the direction in which they were taking Big G. And boy did it pay off, because this is an epic confrontation that deserves to be mentioned in the same breath as cinematic dream matches like Frankenstein Meets the Wolf Man and Freddy vs. Jason, yet perhaps even more impressive, since it represented a clash between characters owned by two different companies. This is a fun, all-out main event kaiju grudge match that sets a new tone for the series. If you can get past the rubber-suit King Kong (a far cry from Willis O'Brien's groundbreaking stop-motion work), and the retcon enlarging of the big guy to match up to Godzilla's size, this one is a great ride.Mothra vs. Godzilla (1964) a.k.a. Godzilla vs. The Thing
Many consider this the best of the Showa Godzilla sequels, and I can understand why. It's the first time Toho had ever matched up two of their own creations, and the special effects are quite impressive for the studio. Legendary FX director Eiji Tsuburaya outdoes himself, using Disney's innovative compositing camera for some shots, as well as a bit of stop motion for some of the close-up fighting shots. The dubbing in the English version is probably the best you'll ever get from Toho films of this era, the human characters are all very engaging, and the songs Ifikube wrote for Mothra's tiny fairy twins are hauntingly memorable.Ghidrah, the Three-Headed Monster (1964)
This is another favorite of Godzilla fans, and introduces the giant lizard's greatest foe, the titular alien dragon. It features the largest assemblage of Toho all-stars yet seen at that point, as Mothra rallies Big G and Rodan to combat the extra-terrestrial menace. This film is also important because it marks the beginning of Godzilla's gradual evolution from villain to hero, as for the first time, he is fighting off a threat even worse than himself, thereby inadvertently benefiting the human race as a result.
Invasion of the Astro-Monster (1965) a.k.a. Godzilla vs. Monster Zero
There are some who point to this as the beginning of the series' downward slide in quality. I'll admit that it takes the camp absurdity to all-new levels, with Godzilla and Rodan kidnapped to the moon by brainwashing aliens, but I still consider it a lot of fun. By this point, the heft of the original film is completely gone, in favor of monster action and spectacle. Plus, we get the X-illians, the series' coolest alien invaders, who would return in 2005 for Godzilla's last outing, Final Wars.Godzilla vs. The Sea Monster (1966)
This is the first time director Ishiro Honda and composer Akira Ifikube stepped aside, and boy does it show. Lesser helmsman Jun Fukuda takes over for Honda, producing one of the most lackluster films in the series. The plot is forgettable, the suit looks cheaper than ever, and Godzilla's foe this time out, a giant lobster named Ebirah, is simply not up to snuff. This one is lacking in the grandiose sensibility of the ones that came before it.Son of Godzilla (1967)
If you're looking for the point at which Toho decided to abandon the grown-ups and go for a predominantly kiddie audience, this would be it. Kaiju flicks had long been favorites of Japanese children, but this is the first time the studio seems to be outright pandering to them. We get the infamous smoke-ring blowing Minya, complete with a silly theme provided by Ifikube that's a far cry from the maestro's earlier masterpieces. And the suit used in this movie is probably the worst-looking one of them all, making the once-terrifying Godzilla look like a cartoon version of his former self.There's no doubt that the series was slipping by this point, both in quality and box office receipts. But it would by no means be the end, and there were certainly some better days to come. Join me next time for part 3, in which Godzilla goes green, invades New York, battles a giant cockroach, and speaks his first on-screen dialogue (!).