Star forts on every continent

Moderate18 supporting entries

Strength is how much of our gathered material lines up with the pattern. It is not the odds that the idea is true.

The working idea

The same pointed-bastion star geometry shows up in the Netherlands, France, Denmark, Finland, Russia, the US, Japan, Sri Lanka, Taiwan and South Africa, with dates spanning 1593 to 1866. Several sit on islands or marshes, several never fired a shot, and several are recorded as built in a few years. Common sense asks why an identical, labour-hungry geometry was worth building in such far-apart places, and whether all of them were built for war at all.

Strongest examples

GoryōkakuA European five-point star in 1860s Japan.

Neuf-BrisachA whole octagonal star town in about five years.

Fort Jefferson16 million bricks on a remote coral key, never finished.

The evidence

Star forts in oldworld.json

18 in 10 countries on 4 continents (US 7, Netherlands 2, France 2, Denmark, Finland, Russia, Japan, Sri Lanka, Taiwan, South Africa 1 each); 17 of 18 marked 'suspected'

18 entries

Recorded build time of 5 years or less

4 entries

Never fought, never finished, or later rebuilt from ruins

5 entries

Island, marsh or coral sites

5 entries

Open questions

Are the angles and proportions the same from fort to fort?
Were some forts built on older earthworks or foundations in the same shape?
Where were 16 million bricks made for a coral island?

What would support it

Older earthworks or foundations in star form found under recorded forts.
Matching measurements that point to one design source.

What would rule it out

Engineering treatises (the 'trace italienne' and Vauban's manuals) explaining the shape as artillery defence, plus dated build contracts. Much of this is already on record for the European forts.

Selection bias

High: only star-shaped forts were collected.

The rating counts how much of our gathered material lines up with the pattern. It is not a probability that the hypothesis is true, and every count is limited by which buildings were picked for the app (see 'selectionBias' on each card).

Next hypothesis

Moderate18 entries#12Older cores behind newer facesOver and over the record itself says a 'new' building sits on, around or inside something older: a surviving medieval hall, a re-used palace core, a refaced 18th-century block, an old fort, prison or citadel site, a temple under a church. Common sense: if this is admitted in these cases, the same thing may have happened in others where nobody wrote it down, and the 'built' date may really be a 'refaced' date.

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