The Devaluation of Huvishka's Coinage
The regions conquered by Kajula Kadphises and Vima Taktu had been divided amongst a number of rulers, and each was using their own weight standards and coin types. The Kushans issued regional types broadly conforming to these local types and weights. Vima Taktu initially followed this practice, issuing what MacDowell (1968) identified as three different 'regional types'. The northern, 'Bactrian' issue was in two denominations 12g and 1.5g; the middle, 'Gandharan' in 9-10g and 2g; and a southern, 'Indian', type struck to 4g. However, early in his reign the coinage was standardized and a single coinage was issued across the whole empire, with a new weight standard of about 8g.
This was the first of a number of major reforms the Kushans made to their coinage. The next king Vima Kadphises introduced a gold coinage, and revised the weight standard of the copper. MacDowell argued that this new standard was struck to the old Attic standard current in Bactria under the Greek kings. For this reason he named the largest denomination the tetradrachm. The idea has some merit and the name has stuck, being the standard one used to refer to the Kushan copper coinage. This general pattern remained the same for the future Kushan kings, a gold and copper coinage being issued in parallel, each with its own weight standard.
Huvishka continued the tradition begun under Vima Kadphises. However, at some point during his reign he substantially reduced the weight standard on which the copper coins were based. That this was a reduction in the weight of the old standard, rather than a new standard, is clear from the dies. The coins shrink slightly (from an ideal of about 3cm to about 2.5cm), but they continue to be struck with a die designed for the full weight coin, so that on any surviving Huvishka coin only part of the design is visible.
Note, it is actually slightly inaccurate to call this reduction in weight a 'devaluation' because as explained below the effect was to over value the coin against its intrinsic worth.
MacDowell (1960) and Chattopadhyay (1967:206-8) disagree over the details of this devaluation. MacDowall believed that it started under Huvishka and proceeded in three stages, with a different reduction being implemented for each of the obverse types. Chattopadhyay proposed a different scheme (and slightly different standards at each stage). He believed that the devaluation actually began under Kanishka and that the dramatic devaluation as a single step.
The difference in weights between the two should not be exaggerated, as the copper coins are often struck only loosely to the standard in force, and this combined with wear can make assessing the exact standard very difficult.
An analysis of coin weights found in the northern regions of the Kushan Empire is informative. In Bactria, only the heaviest denomination (usually referred to as the tetradrachm) circulated in any significant number, and in Gandhara finds of the smaller denomination are still relatively rare. this means that a chart drawing on these regions provides a good indication of the weight of the largest denomination, the Tetradrachm. Though from Vasudeva onwards the problems are complicated by the difficulty of distinguishing the coins from their successors and imitators.
|Vasudeva (and imitations/successors)|
|Kanishka II (and imitations/successors)|
The sample is based on the collections of Herat and Kandahar museums, and finds at Takhti-Sangin (MacDowall & Ibrahim, 1978, 1979; Zeymal 1997; Facena et. al. 1993; Rahman, 1970). The broad outline is clear (change of Weight standard under Wima, significant devaluation under Huvishka, and a further devaluation under Kanishka II). There are several problems. Firstly, the samples are relatively small, because these reports are not common. Secondly, even in these reports most coins are not pictured and the assignement of the coins for Vasudeva and later kings is difficult. This is particularly a problem for Huvishka types where their is rarely more information than 'early' or 'late'. This makes checking the details of MacDowall's or Chattopadhyay's scheme difficult.
It is an obvious question, why the Kushan king would devalue the coins. Ancient coins are not tokens, like modern currencies, they are made of precious metals (bronze, copper, gold, silver, etc) which are actually valuable in and of themselves. So while reducing the weight would allow more coins to be minted from the same amount of copper, it would not increase the value, as someone would still expect to be paid the same weight whatever number of coins that was.
However, if the coins were fixed against some other valuable item then it would be possible to reduce the weight and still retain some of the coins value. The Kushans did this with their gold coinage. Each gold coin was worth a specific number of copper coins. The original purpose of this was probably simply to standardize the copper value in the cheapest possible way. The chart above shows that even tetradrachms struck to the same nominal standard could vary by several grams. Looking at the weights of gold coins (Mukherjee, 1978) is instructive. Of 61 coins weighed in the Indian Museum 57 fall between 7.5 and 8g, and most fall within a few tenths of a gram of the standard (which was about 7.9g). This is an incredibly tight standard compared to the copper coinage, and its purpose is no doubt to ensure that each gold dinara was worth the same amount. It probably also required considerable effort. Rather than in engaging in the same effort with the copper coins, the Kushans simply guaranteed an exchange rate against the gold, ensuring that all copper coins (despite the slight variation in weight) were of the same value.
MacDowall proposed that Huvishka exploited this by reducing the weight of his copper coinage, but retaining the guarantee against the gold coinage. He thus increased the value of his copper 50-70%. This would have allowed Huvishka to spend a far greater amount than he really had, an opportunity few rulers would be likely to overlook.
It is important to realize that this is nothing like the debasement of Parthian silver in the first century, or the gradual adulteration of Kushan gold coins with silver. Both of those are lies, in which the minting authority tries to pass off a less valuable coin at a higher rate. In this case it was very obvious to everybody that the metal content had been devalued, but it retained a higher token value because it could be exchanged against the intrinsically valuable gold coinage. Attempts like this (to in effect create a token coinage) usually ended in disaster in antiquity, but not because there was a deliberate fraud being perpetrated.
This was not a new practice, the emperor Nero had done something very similar with the Roman Silver coinage about a century before Huvishka (MacDowell, 1968 & 1992). So some of the effects of such a policy are well understood.
The intended effect, for the Kushans, was to allow them to spend more money than they really had. That goal was what concerned the minting authority, and it is important to remember ancient governments did not care about economics the way modern governments do and their interest probably did not extend beyond that initial goal. However, the secondary effect was to place a coin in circulation which was worth more than its intrinsic copper value. Undoubtedly the public looked to exploit this for profit.
Firstly, they could forge the coins. If a coin is worth more than its intrinsic value turn copper into coins, and they can be exchange at a profit. The larger the devaluation, the greater the profit. Forgeries of Kushan coins were not uncommon in this period, but they give the subjective appearance of becoming far more common in the reign of Huvishka, and proliferating across the empire, and proliferating across the empire..
Secondly, traders could profit, legally, by exporting the coins. There were now two different weights of coin in circulation, the old tetradrachm and the new, but inside the Kushan empire these two coins were worth the same amount. This amount will have been more than the copper weight of the new weight, but also slightly less than the copper weight of the old weight. A trader could therefore gather old coins (of Wima, Kanishka, and early Huvishka), transport them outside of the empire, and exchange them on the basis of their intrinsic copper value, at a profit. A practice Roman traders are known to have engaged in when Nero devalued the silver coinage.
The evidence from eastern India shows this second activity (see sidebox). Hoards in this region consist of mixed groups of Wima, Kanishka, and Huvishka, and according to MacDowell (1977:46) the reduced weight coins are never found amongst these hoards. Later hoards also have a tendency to consist only of the coinage of Vasudeva, no doubt driven by the further reduction in weight of Kanishka II.
Some Doubts and Further Research
The broad outlines of both Huvishka's devaluation and the effects it had are soundly based. However some of the evidence is thinner than it should be. Though MacDowall claims no reduced weight coins are found in eastern India, the reports from the region are woefully inadequate to check that conclusion. Also, the details of the devaluation are not clear, exactly when in Huvishka's reign it happened, how smooth or dramatic the break was, whether there were any regional variations, and the number of stages involved, are all questions that need answers. MacDowall's analysis was excellent but it was only a tentative first step, and there is a great deal more a detailed study of the weight system of the coppers could tell.