Ewen: the pedometer is one of those pod things that go on your shoe and talks to the Polar watch such that if the calibration is good you can get a fairly accurate read-out of pace on your watch. I agree with your comments on the difficulty of using the heart rate as a guide to pace, and really don't intend to do that. I'm leaning more and more towards leaving the HRM at home.
So running. Yesterday, Saturday, I got out the door reasonably early and just went for a little blat around the block. Two times 3.3 km loops from the front door. The first was at an average of 4:15/km and HRavg of 139. The second was 4:04/km and HRavg of 149. These numbers clearly spell out the truth in Ewen's comment. If I were to say that 149 is my "race" heart rate and follow that, I'd probably run a lot of the first half othe race at sub 4:08/km, and some of the downhill parts at sub 4:00/km -- and subsequently go to pieces late in the race, especially on the uphill pull from 35 to 41 km.
This morning I just ran to Yoyogi Park (5.2 km) ran one 2.5 km loop with Colin, Gareth & Alexei, then ran home again for just on 13 km. Nothing too exciting in the heart rate or pace data.
I'm about to leave and go to the National Stadium to watch the start of the Tokyo Women's International Marathon. Four Namban ladies are running: Mika T, Mika K, Yoshiko, and Satohi. I have been coaching Satohi. After running 3:27 to qualify, she had set herself a rather ambitious target of 3:15, but we have settled on 3:17 as probably being the A goal. She has trained very solidly, mainly doing aerobic endurance work. I am fairly confident she will go close to going under 3:20, but it is hard to say how she will stand up to the last 5 to 7 km. There is one reasonably nasty little hill at about 38 to 39 km, but she is strong and determined, so I think she will be fine. Go Satohi!! (And Mika and Mika and Yoshiko!)