Awww dang. This thread is descending into one of those dick comparing competitions, despite good information being offered. From an historical and strategic points of view, BOTH raids were pivotal moments in history, but for different reasons and in terms of size and scale (don't go there...) Pearl Harbor was most definitely the biggest, but in terms of impact, Pearl and the US Navy recovered a LOT faster than Taranto and the Regia Marina. Despite the loss of fewer capital ships in Taranto, the raid was a severe blow to Italian pride and their ability to successfully challenge the Royal Navy in the Mediterranean. It was a master stroke in tactical and strategic planning and achieved exactly what the navy wanted it to, that of reducing the impact of the Italian fleet in the Med. Its success arguably affected the Italian fleet in subsequent battles, such as Matapan. Did the Japanese achieve the same at Pearl? Not at all. In fact, it infused the Americans with a resolve that would end the war, with the development and deployment of nuclear weapons - that was the strategic impact of the Pearl Harbor raid. It backfired on the Japanese, not to mention their own tactical mistakes.
So, the next point that is of interest, to me anyways is whether Taranto 'influenced' Pearl. Maybe; it's debated and claimed to be the case. I'm pretty certain the Japanese would have studied the impacts of Judgement, no doubt in my mind, but documentary evidence is scarce to what extent it actually influenced their strategy or tactics. What is known is that the whole idea of sinking warships in their own anchorages was initially ratified as policy within the Royal Navy long before Pearl and Taranto. The latter was the actioning of policy that had been discussed many times before within the Admiralty and even before the outbreak of the Great War in 1914, the promise of using aircraft to disable ships in their home anchorages had been proposed.
The British even went as far as to plan such a raid against the German High Seas Fleet in 1919, using aircraft carrier based torpedoplanes not much less sophisticated than the Swordfish, for such an attack, called a 'Copenhagen' in naval parlance after Lord Nelson's attack against the Danish fleet in 1801. Needless to say, resources, which involved the converting of merchant ship hulls into flat top carriers, were devoted to countering German submarine warfare from early 1917. So the raid took longer to prepare for than its supporters, Adm Sir David Beattie being its foremost protagonist, chafed at the bit to action it and saw delays as typical admiralty stalling.
How did the Japanese get wind of this? In 1921, the British Naval Mission sent torpedoplanes and instructors that were involved in the planning and training of aircrew in torpedo dropping techniques to the IJN's naval base outside of the greater Tokyo area at Kasumigaura. Did this activity contribute to the planning of the Pearl raid? Almost certainly in terms of training of techniques. The Japanese took what the British taught them and ran with it. Their inter-war torpedo fleets grew in size and sophistication to what we know of them at Pearl.
Blame the British.
