From: Iowan in MD/DC
I may veer a bit off topic with this response...
ORIGINAL: Anomander Rake
+1 for resizing style
Again, Japan is limited by supply and heavy industry, so fielding more airplanes does not give Japan the supply needed to fly those airplanes.
I think that many players don't think about this problem and as I saw don't find this problem.
I think also that supply&hevy industry limit doesn't prevent unrestricted resizing.
It is there (the "problem" of being limited by supply/heavy industry), however it is more nuanced than just "Japan doesn't have enough supply sources to feed all the expanded units" (or buy back lots of dead divisions, etc.).
The supply of supply for Japan is somewhat elastic - there are non-Oil, non-Fuel (and therefore non-Heavy Industry) sources of supply available on the map. There is still a finite amount, but it is less constrained than the straight Oil -> Fuel -> HI -> Supplies chain. That is by far the largest source of supplies, so it gets a lot of emphasis and attention.
However, imagine the following hypothetical scenario. Typically Japan does not run short of supplies until late in the war - 1945 sometime, if properly played. Japan also typically has a glut of Resources (unlike Oil) - many more than the Light and Heavy Industry centers will use. It does need to be trucked/shipped around the map, which does cost Fuel (which in turn constrains HI), but a judicious player should still have a few million extra Resources sitting around in a "normal" game (I never hauled out of Sumatra, for example, which produced 1M+ Resources in 3 years). There have been arguments about whether or not to expand Light Industry, which does not provide a "return" on the supply invested until 1100 days after the expansion. This means the investment will only start to pay off 3 years afterwards and needs to be done as soon as possible (and definitely not after June 1942, probably) or else Japan risks running out of supply during her critical expansion phase. It would also need to be done on a large enough scale to make a difference (say, +2000 LI) - which means that it will need to be done over a multitude of locations. And it also costs 2.2M supply to conduct that expansion, which is what the kids used to call a "buttload." But consider what could happen if Japan were to capture a large stockpile of Allied supply somewhere (300K, say at Colombo or Calcutta or Pearl Harbor) early in the war. Doing so could help buy Japan more units with which to slow down the conquering tide. Supply buys more sandbags.
The -10% efficiency to Japanese refineries is a reason why I'll never play any DBB scenarios that change that ratio without either changing it back or changing it to a 10:10 Oil to Fuel production ratio (instead of 10:9).