1970's "Gamera vs. Monster X" ("Gamera tai Daimaju Jaiga" or Gamera vs. Giant Devil Beast Jiger) was the 6th Gamera entry in the Daiei series (only "Gamera vs. Zigra" would follow), arriving during a lean year for Toho with the passing of effects master Eiji Tsuburaya, a new team releasing "Godzilla vs. The Smog Monster" in 1971. The child friendly focus for once strikes a balance with the rest of the human cast, the usual Japanese/American duo a bit older here though one little sister persistently annoys with her nonstop chatter. Obviously sporting what seems to be the highest budget since "War of the Monsters," the last sequel to show a metropolis being smashed to pieces, here set in Osaka where the World's Fair Expo '70 will take place throughout the year (there's even a mention of the lost continent of Mu, depicted in Toho's 1963 "Atragon"). Much of the opening reel is given over to the location and goals of the promoters, intending to recover an ancient statue called 'The Devil's Whistle' on Wester Island in the central Pacific, supposedly bearing a curse of death to anyone who tampers with it. Gamera surprisingly but unsuccessfully tries to prevent its removal from the ground, the ship's crew infected with some type of unidentified virus before they reach Osaka. The curse turns out to be real with the emergence of Jiger, a quadruped monster that incapacitates Gamera by firing sharp quills into each of his limbs, occasionally leaping to great heights when not using a Barugon-like heat ray to fry human debris (in a nice gruesome touch, they all turn into skeletons). A curious sound informs us why the statue earned its name 'The Devil's Whistle,' and the teen pair surmise that it gives off a kind of poison linked to Jiger, now a definite threat to Expo '70 as well as the rest of the planet. Gamera recovers from the first assault and again gains the upper hand against this unorthodox opponent, only for a new challenge that again puts him out of action, an injection from Jiger's tail that produces a larva growing near the turtle's lung. Here is where Japanese Hiroshi (Tsutomo Takakuwa) and American Tommy (Kelly Varis) use their knowledge of an experimental minisub to take a trip inside a waterlogged Gamera, obviously inspired by Stephen Boyd's classic "Fantastic Voyage," resulting in simple radio waves destroying the baby Jiger so that Gamera can finally use the statue for one ultimate purpose, cleaving Jiger's head with but a single shot. The physical look of Monster X may not look that impressive compared to previous foes but there's no shortage of surprises this time around, easily the best sequel since number three, "Return of the Giant Monsters." The usual annoying brats are actually slightly older and even useful for a change, leaving Katherine Murphy's grating tiny tot incessantly complaining during a beleaguered Gamera's attempts at redemption (all three seem to be directing the titular turtle at every stage). Things would promptly descend to rock bottom with original series finale "Gamera vs. Zigra," where director Noriaki Yuasa seems to be going for the preschool crowd!