And now, as The FT reports, the real "whale" of the Japanese markets is stepping up its buying (up over 70% YoY) entering the market on down days more than half the time in the last four years.

Since the end of 2010, The FT notes that the BoJ has been buying exchange traded funds (ETFs) as part of its quantitative and qualitative easing programme. The biggest action began last July, when its annual acquisition target was doubled to ¥6tn. Since then, the whale designation has seemed pretty obvious: the central bank swallows a minimum of ¥1.2bn of ETFs every single trading day (tailored to support stocks that further "Abenomics" policies), and lumbers in with buying bursts of ¥72bn roughly once every three sessions.

Some traders say the bank's supposedly targeted buying has cushioned the whole market. Last year, foreign investors were net sellers of ¥3tn of Japanese shares - a retreat that might have decimated benchmarks had the BoJ not swum in with ¥4.3tn of support via ETFs.

And so it was no big surprise that Kuroda and his pals were active once again this week. As Dennis Gartman notes, Jeff Uscher, in his daily commentary on the Japanese capital markets, sees the fingerprints (or footprints) of The Bank of Japan "Correction Protection Team" on the job.