If there are no outside liberties, this 6 points large eyeshape can be turned into territory or seki. Either lives with 5 points of territory. ( also does that, but White will have one ko threat in each case and that threat will be smaller after .)
Whether White should begin with or a depends on what kos might be created elsewhere before this seki is reached, as well as on whether eventual reducibility to bent four in the corner means death.
(As I don't fully grasp miai counting I'd rather have someone else talk about that.)
- SAS: Note that 5 points is only correct under Japanese/Korean rules. Under almost any other ruleset the deiri value is only 4 points, since Black would have a point in the seki anyway. As usual for double gote plays, the miai value is half the deiri value (so 2.5 or 2).
The Count: Under area scoring, if Black plays first, he gets all of the "gun six" points (6 more than White). If White plays first, she gets 2, Black gets 2, and 2 do not score (Black and White have the same number). Therefore, the deiri value of a play is 6 points, not 4, and the miai value is 3 points.
Harleqin: You can actually see those three points:
Both change ownership from Black to White, for one point each. Both change ownership from Black to neutral, for a half point each.
By the way, every move counts one point more under area scoring - the point it occupies.
The Count: Of course, you're right H, but it is perhaps a bad place to mention it, since in this example Black has an eye in seki and White does not. So under Japanese rules, the miai value of a play isn't 1 point less than 3, rather it's 2.5. Could we just remove the erroneous statement above and say what the miai value of a play is under area scoring, Japanese rules, and territory rules without the special seki rule?