The sylibic you speak of is found at bottom under ribbon that say 6 sen and between where racetrack oval kinda forms a triangle. Im no expert, but ones with a backwards looking E are said to be very rare this one here appears to have an I shape. Hope this helps a little.
This is an interesting puzzle! I have never looked at this issue before so there is perhaps very little I can add.
However, from what I have read, if this stamp is genuine and it has a syllabic it can only be one of seven syllabics: 10, 11, 13, 14, 15, 16 and 17 as the later plates put the syllabic in a different location within a frame.
I agree that none of these seven (or any of the others that ClassicalStamps mentioned) matches what we see here.
However, my only references for this are the illustrations in SG and Scott and the genuine examples I've seen online.
I've had a look at a number of genuine 6 sen stamps online and none looks quite like this one.
In particular, I've not see the region of arcs above the chrysanthemum slanting from left to right at the base as here.
I would assume this is a forgery but would be very happy to be proved wrong.