Wow, thanks so much for all the comments of sympathy and encouragement. That's a good way of finding out the lurkers, just post that you have an injury, ha ha! I'm afraid what I have to tell you is going to wear thin your patience and forbearance.
Moving around this evening from work to Shibuya and up Dogenzaka to attend a kind of interview, involving a fair bit of walking, it struck me that there was not much pain or even discomfort coming from the sore bit. My mind got to working. Every day in September. Every day in September. Maybe you can still do it? I trotted a little bit in my work clothes. Hmm...doesn't hurt. No, don't be foolish! I tried to shove such thoughts to the back of my mind. So on the way back from the interview I popped into Tokyu Department Store 8th floor above Shibuya Station. There is an Osaka goods promotion (until Oct 2), and prominent among the stands was one from a craft brewery, Minoh Brewing. Their double IPA (9% ABV) was extremely tasty (both glasses), as was their real ale style stout. I got home at 9:30 and only Kohta was home and he was engrossed in his Play Station (Final Fantasy XII for those who are interested in such things).
"Hi Kohta!" I said. "Gomen ne, demo chotto atama ni byouki desukara, kore kara chotto hashitte dekakimasu." (sorry mate, I'm, a little bit sick in the head, so now I am going to go out for a little run." -- apologies to those who speak proper Japanese)
I thought that my 3.3 km loop would be enough to satisfy the "run day" requirement. But I moved well, the evening was extremely pleasant, I had a nice little buzz on from the Minoh beer, the leg wasn't too uncomfortable as long as I kept to an easy pace, so I added on a lap of Rinshi no Mori (forest park) to come up with 5.3 km at 5:18/km, HRavg 125.
It was definitely as much as I could hope for, especially considering I had tried so hard to reconcile myself to taking a day off, and I would like to think it did not set back the sore bit too much. At times I also had the thought that, well, you know, this is what I enjoy, this is what I get off on. Just the sheer pleasure of moving along, breathing easy, feeling alive. Kind of like 2P's happy place. So what if I endanger my marathon? Just as Naoko Takahashi said that running is about more than the Olympics, so too can I say that running is about more than a sub 2:55 Ohtwara. So I just enjoyed the run, sore leg be buggered.
Well, I know I am a SFI, but I promise that I am going to keep things very easy and next week really concentrate on cross training, just as some of you suggested in the comments, e.g., Toshihiko Seko. Sure I can get away with these little gentle runs, but if I am going to get to the start line in better shape, I have to give the leg a real chance to of coming good so I can fit in a couple more quality weeks down the line a bit.
Thank you for understanding this poor, sick, addicted runaholic.