My interpretation of Жили-были старик со старухой у самого синего моря is:
Once upon a time, there lived an old man and woman by the most blue sea.
Once upon a time, there lived an old man and woman by the bluest sea.
However, both Google and Yandex translate самого синего моря as simply blue sea, not bluest sea.
What is the meaning of самого in the sentence?