I like to deconstruct sections of verses to try to understand what Bryon was actually telling us. I believe this is one of the only ways that we will progress in this treasure hunt.
Let's take a look at the oft overlooked first five lines of Verse 6.
Verse 6
Of all the romance retold Men of tales and tunes Cruel and bold Seen here By eyes of old
Many will read this, call it a reference to Treasure Island, then move on. The goal with deconstructing the verses is to look at each line and ask "What is Bryon trying to tell me?"
Line 1: Of all the romance retold
The first question we can ask is, what types of things are "retold"? Your nearest dictionary will tell you that "to retell" is to "tell (a story) again or differently." If "romance" is the thing being "retold", then we can make the connection that "romance" is related to or a type of story. In the 80s, this may have taken your mind to Harlequin novels. Luckily we have the Japanese hints to set us straight:
Start analogizing from the word "romance". Not "Romance" in Japanese (Japanglish) for romance novels [love affairs, etc.], but medieval Europe's…
The connection between romance and stories, with the help of the Japanese hint, gets us squarely to the era of Romanticism.
Line 2: Men of tales and tunes
Line 3: Cruel and bold
Given the prominence of the "Man and Fair Folk" thematic through most of the front of the book, I tend to pay extra attention to lines like this. The question here is, who are the men of tales and tunes? Again, the Japanese hint gives us a helping hand by asking the exact same question..
What kind of men could they be?
Tales and tunes, stories and song, this might make you thing of the Bards.. Shakespeare or Robert Burns, but they don't meet the criteria of being "cruel" and "bold".
The dictionary definition for cruel is "willfully causing pain or suffering to others, or feeling no concern about it." While bold is defined as "(of a person, action, or idea) showing an ability to take risks; confident and courageous."
So we're looking for Men of stories and song, who are both courageous and willfully cause suffering to others. It's not a far leap to get to the idea of Pirates with their tall tales and sea shanties.
Given all of the above, if you start looking for a Romantic Era story about Pirates... There aren't a lot of options. It won't be long before you find your way to Treasure Island's opening "To the Hesitating Purchaser". Verse 6's similarity to which acts as our confirmation that we're on the right track.
The first line of "To the Hesitating Purchaser" reads:
If sailor tales to sailor tunes,
Now we have an answer to the question posed by the Japanese hint. The "Men" of "tales and tunes" are sailors.
Line 4: Seen here
Line 5: By eyes of old
The next two lines, the last two that we'll review tie it all together. The first question we should ask is: where is "here"? Bryon is describing a place. Likely a place that he was standing when he wrote this line. Whether it's the beginning, or the end, he is telling us about some physical location that is important to this verse.
Let's not forget that it is the "Men of tales and tunes", the sailors, who are the ones seen there.
The idea of sailors on their own is quite vague. You could see sailors in a whole lot of places. To help us, he further describes the location. Before we get into that, we have to detour through a concept called equivocation.
If you're not familiar, equivocation is "the use of ambiguous language to conceal the truth". The ambiguous language is in line 5, a tiny little word -- "by".
With respect to something being "seen", the word "by" has two distinct uses:
In proximity to. Near. e.g. "standing by the window"
through the agency. e.g. "a poem written by Keats"
Applying this to lines 4 and 5, we have two interpretations:
Seen here by eyes of old, as in, a thing known as "eyes of old" is doing the seeing here.
Seen here by eyes of old, as in, seen here near a thing known as "eyes of old"
In both cases, "eyes of old" is the noun. It's either the thing seeing the sailors or it's the thing near the sailors. Either way, we have to ask the question: "What is eyes of old"?
In the first interpretation, the obvious choice might be a statue or something that can actually "see", within some reasonable definition. The second interpretation is more challenging, as it could be anything that a riddle might call "eyes of old". Given Bryon's precedent of using words like "near", "nearby", and"not far away" in other verses, I tend to lean towards the second.
Conclusion
We can boil these five lines down to something like this:
Find the place where sailors are found near something called "eyes of old".
If you can find this place, I guarantee you are within a few hundred feet of the casque, if not right on top of it. The only thing left to do is solve for the riddle, "eyes of old".
If you doubt this approach, think about the first four lines Verse 3 and how that gets you to the "North Area".
..And there they lay—aye, damn my eyes!