Tokyo cost of living

It varies by person, but what would be the minimum per month that an individual can live in Chiyoda(Tokio) or any place with access to Chiyoda?

The minimum also varies by person. One person's must have is another's frill.

Chiyoda-ku stretches across a vast area, but generally it is a business district, where the daytime population is more than ten times the nighttime population. People who live in Tokyo generally commute, even if they earn a good salary.

"Access to Chiyoda" is a meaningless concept - everywhere has access to Chiyoda-ku, and Chiyoda-ku itself is so big an area that even defining your criterion as something like "within 30 minutes by subway" is meaningless unless you specify a particular station within Chiyoda-ku.

The minimum would be 100k JPY/month (k=1000).

I have checked minimum prices for a room by
http://www.homes.co.jp/chintai/tokyo/city/price/
and commuting costs (and needed one-way times) by
http://www.jorudan.co.jp/norikae/teiki.html

city pref. total room commute time
Chiyoda-ku Tokyo 105k 105k 0 0
Ome Tokyo 58k 33k 25k 1:27
Kodaira Tokyo 72k 45k 17k 0:51
Ayase Kanagawa 63k 38k 25k 1:05
Sanbu Chiba 62k 26k 36k 1:36
Kumagaya Saitama 65k 34k 31k 1:16
Rygasaki Ibaraki 58k 27k 31k 1:15

So, minimum would be 60k/mn (with 1.5 hour one way commute).

http://www.hitori-g.com/life/
gives other costs of 40k/mn (minimum: food 20k/mn and others).

In total, 100k/mn for minimum.

50% up would be average. 100% up for Chiyoda-ku.

But the initial cost should be much higher.
http://hitorigurashi-navi.net/cost.html
gives minimum : 500k and average : 700k.

Even in Tokyo, 180k yen a month is pretty comfortable to afford the bare necessities to me (rent, utilities, internet, food).

YMMV.