A prewar postcard of a stretch of the old Tōkaidō, by Lake Ashi(-no-ko) in Hakone:

Still there!

Hakone as a place name shows up in the Man'yōshū, in the "Eastern poems" like this one from Sagami (#3370):

安思我里乃 波故祢能祢呂乃 爾古具佐能 波奈都豆麻奈礼也 比母登可受祢牟
Asigari no/ Pakwone no nero no/ nikwogusa no/ panatuduma nare ya/ pimo tokazu nemu
Is she/are you a "flower-wife", like the soft grass on the peak of Mt Hakone of Ashigara? [No, she is/you are not, but] I shall sleep without undoing my garments [i.e., alone].

(As usual, original orthography and romanization following Frellesvig et al. 2014. Greasemonkey script to replace /p/ with /h/ and/or /f/ currently under development.)

What's a "flower-wife"? The standard theory in cases like this is that it is a partner who can only be admired, not touched, perhaps due to some pre-wedding taboo.

Incidentally, you may have noticed that the fourth line as recorded has eight morae. People have wondered since at least the Edo period* whether this might not be a scribal error. Simply removing the 都 would reduce the mora count to the expected seven and also change the word from /panatuduma/ to /panaduma/, which is the normal way the word is written.

(In fact, looking through a couple of dictionaries I don't see a single citation of any other instance of /panatuduma/, and the Jidaibetsu Kokugo Daijiten at least specifically mentions the 都-is-an-accidental-insertion theory.)

Works cited

• Frellesvig, Bjarke; Horn, Stephen Wright; Russell, Kerri L.; and Sells, Peter. The Oxford Corpus of Old Japanese. 2014. <http://vsarpj.orinst.ox.ac.uk/corpus/>.
• Ide, Itaru 井手至 and Mōri, Masamori 毛利正守, eds. Shin Kochu Man'yōshū 新校注万葉集. Tokyo: Izumi Shoin, 2008.
• Jidaibetsu Kokugo Daijiten: Jōdai-hen 時代別国語大辞典 上代編. Tokyo: Sanseido, 1967.