Hi Brian,
Please check lower down on the keyboard product pages 🙂
There is a diagram of the factory default keyboard mappings, where the Function key’s location is noted on both the HHKB style split right shift keyboards and the non-split shift keyboards.
On split shift keyboards the key is the 1U key to the right of the smaller right shift key.
On the other keyboards the factory default Fn key is the right Ctrl key. The name of the key remains Ctrl on the printing, though you can purchase a key labeled Fn for that spot on the extra keys product page (most people opt for the default included Ctrl key and not a custom printed key).
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