Did Space Invaders cause a shortage of 100 yen coins?
1978 saw a mintage of 292 million coins, will under the mintage for the years before and after. So if there was an increase in 100 yen coin production, it was from an unusually low baseline, and surely not a tripling of production as sometimes claimed. If it was a low-mintage year, it might not have taken much of a demand shock to cause local shortages. There did seem to be a period of higher mintages in the 1979-1981 period. I wonder if that had anything to do with the video game craze or if it was just a coincidence...
I was shocked when I first lived in Japan to find that coin-op games cost 100 yen, compared to 25 cents back in the US. At mid 90's exchange rates, that was about a 4:1 price difference. Almost everything is more expensive in Japan, but not usually by that large a factor. In 1978, the exchange rate was about 210 yen to the dollar, so the discrepancy would have only been about 2:1 originally. Because of relatively higher US inflation in the late 70s (Thanks, Carter!) the real cost of video games dropped much faster in the US than in Japan for the same nominal prices.
It's actually pretty remarkable for something to keep the same price from 1972 (the introduction of Pong) to the late 1990's (when arcades pretty much died out in the US). If the CPI was about 42 in 1972 and rose to about 155 in 1996, that's almost a fourfold decrease in real cost over those 24 years. Decreasing costs of integrated circuits allowed electronics costs to fall when everything else went in the opposite direction...