Many
 occidental
 megalopolises
 have
 experienced
 a
 dramatic
 polarization
  between
 a
 vibrant
 and
 intense
 town
 center
 and
 a
 suburban
 sprawl
 eventually
 mag-­‐ nified
 and
 encouraged
 by
 large
 retail
 centers
 linked
 to
 highway
 hubs.
 On
 the
 oppo-­‐ site,
  Tokyo's
  compact
  megalopolis
  has
  succeeded
  in
  the
  display
  of
  a
  city-­‐region
  scheme
  with
  a
  polycentric
  structure
  (Frey,
  1999).
  Outside
  the
  railway
  ring
  of
  the
  Yamanote
 line,
 there
 are
 suburban
 centralities
 accumulating
 almost
 the
 same
 vari-­‐ ety
  of
  urban
  functions
  that
  the
  inner
  city
  center.
  As
  a
  consequence
  of
  an
  urban
  planning
  deeply
  tied
  to
  vernacular
  logics,
  these
  peripheral
  centers
  exemplify
  today
  a
  way
  of
  sustainable
  urban
  metabolism
  that
  manages
  to
  create
  attractive
  urban
  ambiences.