The most objective measure is to track the Japanese CPI over time which does NOT show a 27 percent deflation. The fact that the Yen has appreciated or depreciated relative to another currency is not an objective measure.
That presumes that government CPI accurately reflects credit availability and the velocity of money...which Japan's CPI does *not* do.
If you want to see deflation in Japan, you can look at currency values (27% deflation in the last 10 years)...or you can look at the value of real-estate, say, for the past 20 years.
From 1989 to 2009, Japanese real-estate has deflated 50%.
Deflation.
Japan's Nikkei stock market average has also deflated over the past two decades.
Deflation.
Japan's velocity of money has likewise deflated over the past two decades. Deflation.
Deflation. Deflation. Deflation.
But...if you support Schiff's efforts that have cost his investment clients so dearly over the past several years (more than 30% losses), you are pretty well limited to arguing that Japan somehow didn't see any deflation and that the U.S. didn't see any deflation when FDR was spending so much New Deal money back in the 1930's.
That's a sad side of History to be on, however. Schiff is clueless. He's cost a lot of people a lot of money, and he's been wrong about every economic downturn in History except the one inflationary 1972-1973 recession.