One of the problems with studying Shinto is the names of the kami. First, there are a lot of kami, and they tend to have long names. Masakatsuakatsukachihayahiamëno’oshihomimi no Mikoto, Amaterasu Ōmikami’s son and the mythical ancestor of the Tennō, is a good example. Simply remembering the names is tough to begin with. (Many kami have standard “short forms”; Masakatsuakatsukachihayahiamëno’oshihomimi no Mikoto is normally referred to as Oshihomimi.)
Then there is the problem that many kami have multiple names. Amaterasu Ōmikami is officially called “Amaterashimasu Sumeōmikami” at Jingū, but this one is fairly straightforward, as it is just a different reading of “Amaterasu”, to make the verb more polite, and an addition of a further honorific, “sumë”. However, she is also called “Ōhirumë no Muchi” in some legends and at a couple of jinja, a name that appears to mean “Great Sun Woman who Rules”. The context makes it most natural to assume that this is a different name for the same kami, but there is also the possibility that there were originally two different female sun kami who were merged into one. This is an even stronger possibility with Ōkuninushi, who has eight different names, and in some cases is venerated in different places under different names. There are quite a few people who believe that these were different kami, and, indeed, that every area of Japan originally had its own Ōkuninushi, as the name simply means “Great Lord of the Land”.
And, on the other hand, there are multiple kami who have the same name. There are at least two kami called “Tamayorihimë”, for example, featuring in different legends, supposed to have happened in different periods, in different areas of Japan. Similarly, there are multiple jinja venerating “Ōkunitama”, which means “Spirit of the Land”, and is thought to refer to a different kami in each area — possibly the same kami as the local Ōkuninushi. But maybe not.
Even when you have basic agreement on the name of a kami, there is often no consensus on how to write it, or pronounce it. The Kojiki and Nihonshoki often use different characters to write the names of the same kami, even in cases, such as Susano’o, where it is obvious that the same kami is being referred to. Sometimes, the Nihonshoki has variants for a single kami, but in these cases it is plausible that the characters could be read in the same way. Even today, different jinja not infrequently use different characters to write the names of kami that everyone, including the jinja in question, agrees are the same.
Sometimes, the same characters are read in different ways. The character meaning “hand” can be read both “të” and “ta”, for example, and different jinja may have different traditional readings for the same character in the name of the same kami. Similarly, there can be differences of opinion over voiced and unvoiced consonants. The father of Amaterasu Ōmikami is normally referred to as “Izanagi”, but sometimes the final consonant is unvoiced, and he is referred to as “Izanaki”. Again, that change might be made without changing any of the characters used to write the name, and different characters might be used without changing the pronunciation.
This does not mean that anything goes. Amaterasu Ōmikami and Ōkuninushi are clearly different kami, even if it is not clear just how many different kami. Indeed, in some cases one jinja might treat two names as different kami, while another jinja might treat them as alternative names for the same kami. In the absence of a way to count kami and identify them independent of jinja traditions, we cannot even say that the two jinja are not both right, and venerating three different kami.
This can lead to problems when trying to fit different myths together, or when trying to read (or transcribe for an English text) the names of the kami of a jinja. One simply has to accept these difficulties as part of the fascination of the topic.