How is the あ vowel produced?

Question

I've been reading about the sounds of Japanese and always thought the あ's highest point is shown as in this diagram:

Which I learned narrowly can be transcribed like [ɑ̞] (the diagram is taken from here, which my book also shows it as)

But reading more, I stumble upon for example from the Japanese wikipedia this one:

Which one would be the most correct in most cases?

Answer 1

Both are correct, there is no set-in-stone answer as the difference in pronunciation is slight. As you said, the pronunciation depends on context.