Notes on "The Supply of Money and Reichsbank Financing of Government and Corporate Debt in Germany, 1919-1923" (http://www.piketty.pse.ens.fr/files/capitalisback/CountryData/Germany/Other/Pre1950Series/RefsHistoricalGermanAccounts/Webb84.pdf):

"The velocity index is the wholesale price index times I minus the unemployment rate divided by the stock of high-powered money at the end of the month" (from the footnote to Table 1, page 505)

Why is unemployment in the equation? Unemployment is not in the standard definitions for Velocity.

The definition of "High-powered money" is similarly complex and seems to include non-circulating instruments.

All this data is suspect, and massaging it abstracts even further from what was actually going on.

"The fall of prices raised the real value of the outstanding debt and money supply, however, and this undermined the credibility of the Reichsbank's threat to defeat any run on the mark. Furthermore, after the real values of the holdings of nominal assets reached their equilibrium levels for a state of temporary stability, inflation had to resume at least at the rate of growth of the nominal money supply. Then, confident that the non-speculators would be following them rather than the Reichsbank, the speculators could make their runs on the central bank, as they did on April 18, after which the Reichsbank let the mark resume its fall. In short, exchange market intervention could have a short-run impact on the course of the inflation without altering the underlying process that determined the money supply." (Pages 505-506)

This passage highlights the psychological nature of inflation. If prices went down, "credibility" was undermined. Credibility by whom? Did the individuals making credibility judgments have a choice? If speculators chose not to "make their runs on the central bank", would runaway inflation have occurred? 

"inflation had to resume at least at the rate of growth of the nominal money supply": why?

"exchange market intervention could have a short-run impact on the course of the inflation without altering the underlying process that determined the money supply": what if the US Fed had opened an unlimited swap line with the Reichsbank, "unlimited" meaning both unlimited capacity, and unlimited rollovers? Then the money supply would be permanently disconnected from inflation.

"the decisions by foreign bankers not to give Germany long-term loans" (Page 506)

Again, these are decisions that do not have to be made. During the most recent financial crisis, the Fed facilitated liquidity so that the ECB could continue to provide dollars on demand. Why couldn't the Fed have done a similar courtesy to the Reichsbank?

"it was fundamentally more of a change in what the private sector was asking the Reichsbank to do" (Page 506)

Once again, private sector decisions were crucial in the inflation. The private sector was not an automaton. It was composed of individuals making choices. The choices could have been different, again reaffirming that money supply is essentially disconnected from inflation. Inflation is a psychological phenomenon.

"When the Reichsbank stopped lending to the government in November 1923, it balanced its budget and the inflation stopped. When the Reichsbank cut off credit to corporations in the spring and summer of 1924, they quit speculating on a resumption of the inflation. The effectiveness of the Reichsbank action in eventually ending the inflation shows that its earlier passivity made the inflation possible. Whether the Directors of the Reichsbank are therefore to blame, however, depends on whether an earlier conversion of Reichsbank policy was politically possible. The scope of this paper permits only the report that many historians believe, as I, that an earlier attempt to force either balanced budgets on the government or a contraction on the private sector would have seriously threatened the Weimar constitutional system.[20] In any case, the constancy of the Reichsbank's permissiveness up to November 1923 means that historians should neither blame nor praise it for the major changes in the inflation rate during the first five post-war years." (Page 507)

Weren't other factors in play, such as a lifting of the reparations burden? What happened to the French invasion? Doesn't this passage affirm that speculators caused the runaway inflation? If the speculators had chosen not to make runs on the central bank, would there have been inflation? Were the speculators free to choose not to cause more inflation? Or were they essentially robots programmed to behave in a perversely-incentivized fashion?

It is interesting that the paper cited as refuting my clain that Weimar was not a case of "too much money chasing too few goods" concludes: "the constancy of the Reichsbank's permissiveness up to November 1923 means that historians should neither blame nor praise it for the major changes in the inflation rate during the first five post-war years."

Conclusion: inflation in Weimar Germany was psychological. There was no "too much money chasing too few goods." QED.