In the early 1970s, the annual release of Topps baseball cards was still a major part of the hobby for many young baseball fans. Children would eagerly open packs of the new Topps cards, hoping to collect their favorite players or chase after elusive short printed or serial numbered cards. When it comes to the 1972 Topps set, the card numbers serve as an indicator of scarcity, with higher numbers representing more scarce or difficult to find cards within the set.

The 1972 Topps set contains 556 total cards, including base cards, multi-player cards, manager cards, and checklists. Cards were issued in sequential order from #1 to #556, with the lowest numbered cards generally being the easiest to obtain in packs or in the trading market. Back in 1972, many young collectors hoped to complete their set but may have fallen just short due to not being able to find some of the higher numbered cards. So in the original collecting context of 1972, the threshold of what constituted a “high number” would likely have been considered 400 or above.

Any card from the 1972 set with a number of 400 or higher today would be considered much more scarce and valuable compared to the lower numbered cards from the set. This is because fewer packs from 1972 have survived intact and unsearched over the past 50 years. The play period for these cards was also shorter before they entered long term storage in attics, basements, and collection boxes. Each subsequent year further thins the surviving poplulation of high numbered gems from the vintage 1972 set.

Some key data points help shed more light on why numbers 400 and above are notable as being scarce in the 1972 Topps set:

The checklist card is #555, meaning any card #556 would have been the last possible basic card in the set.

Multi-player cards like the team cards took up higher numbers like #547, #548, #549, leaving less room for true singles cards at the top of the numbering system.

Card production sheets from Topps at the time stated the intended population of cards #481-556 was much lower versus the early portions of the set. This was done deliberately by Topps to create scarcer “chase” cards.

Population census data compiled by tracking registraion and census programs over decades shows far fewer high numbered 1972 cards have been accounted for versus counterparts in the 100-300 range.

Pricing and demand in the vintage trading card market today overwhelmingly favors 1972 rookie and star player cards with numbers 399 and above versus their lower counterparts.

Anecdotal accounts from collectors who opened packs as children in the early 70s commonly note they never saw cards numbered 400 and up despite completing much of the lower numbered portions of the set.

So in summarizing why 400 and above carries significance for 1972 Topps scarcity – the original design of the set by Topps, shrinking card populations verified by decades of data, and demand trends prove the elusive high numbered vintage gems from the 1972 set have stood the test of time as the biggest challenges for completing a set from that classic era of the hobby. Cards like Nolan Ryan’s imposing #523 rookie remain iconic symbols of the ultimate chase at the top of the 1972 checklist almost 50 years later.