method to certify the number of chiral carbons in fischer and haworth projection of glucose

While reading some notes about Glucose and its various projections:


* Fischer Projection: 4 chiral centres


[![Fischer](https://i.stack.imgur.com/I9TBe.jpg)](https://i.stack.imgur.com/I9TBe.jpg)


* Haworth Projection: 5 chiral centres


[![Haworth](https://i.stack.imgur.com/CTYCM.jpg)](https://i.stack.imgur.com/CTYCM.jpg)


**My doubt is that is there any (specific) method (practical) to ascertain the number of chiral centres in both the forms.**


I know that more than 99.5% of glucose exists as Haworth Projection - Closed Ring Structure and hence Linear - Fischer Projection practically does not exist.


But it (linear ie open chain glucose) could be always isolated though difficult.


Thank you!


