Fess
… bar, gemels, label; per fess; barry; chief

The fess, or fesse, is a broad stripe running the width of the shield.

Its depth may be from one fifth to one third of the height of the field, narrower when it lies between other charges, broader when it is itself charged.

Argent, a fess gules — Melville

Or, a fess gules — Colevile

An exceptionally broad fess, occupying half the height of the field, appears on many of the national flags of Spain since the late 18th century.

Gules a xxx fess argent — Spain, Civil Ensign, 1928-1931

Diminutives: bar, gemels, label

When two or three fesses are borne they are normally blazoned bars.

Gules ij bars or — Harcourt

Gules iij bars or — Cameron

Little bars borne in couples are styled gemels.

Sable, a chief and two gemels argent — Melsanby

Argent, a fess between two gemels gules — Badlesmere of Kent

The label is fillet bar across the upper part of the chief, from which hang three, four, five or more pendants, the pendants being, in most old examples, broader than the fillet. It was commonly used as a means of differencing a cadet’s shield, and in the heraldry books it has become the accepted difference for an eldest sun, although the cadets often bore it in the middle ages. In modern armory the pendants are all but invariably reduced to three, which, in debased examples, are given a dovetailed form while the ends of the fillet are cut off.

Or, a label azure — van Oostenwolde

Parted field: per fess

A shield or a charge divided fesswise down the middle into two tinctures is said to be party per fess or per fess.

(party) per fess gules & or — Count of Stockau

A shield divided evenly feswise into three tinctures may nowadays be said to be teirced in fess, although many examples of “teirced in fess A B and C” would likely have been blazoned as per fess A and C a fess B in early English armory. To my mind teirced in fess indicates three bands of even width, whereas the fess of per fess … a fess might be narrower than the bands either side – but maybe such a nicety would have been lost on a mediæval herald.

Many modern national flags are so divided: Estonia, Germany, Netherlands, and so on.

tierced in fess azure, or & gules — Vendramini

“tierced in fess gules, argent & azure”
— The Netherlands

Varied field: barry

When the field is divided evenly fesswise into six pieces it is said to be barry. If the field is divided into four or eight pieces, it is blazoned as barry of four or barry of eight. With ten or more divisions the number is unreckoned and burely is the word.

barry (of vj) or & azure — Oyri

barry of viij or & gules — Fitzalan of Bedale

burely of argent and gules — Stutevile

Related ordinary: chief

The chief is the upper part of the shield and, marked out by a line of division, it is taken as one of the ordinaries. The chief should be marked off as a third part of the shield, but its depth varies, being narrower when it surmounts a charged field and broader when itself charged.

Vair a chief or — Tichborne of Tichborne (13th century)

Distinguishing between a chief and per fess is pretty easy when there are no other charges…

Argent, a chief gules — Menzies

(party) per fess gules & argent — Magdeburg

Argent, a chief gules with six martlets countercoloured — Fenwick

… but in Fenwick’s case the chief needs be (about) the half of the shield to accommodate the martlets, and seems more likely to be blazoned as per fess gules and argent with six martlets countercoloured.

Contrariwise, if a per fess shield is charged in base, the line of partition may move up the field. If the shield was of two colours (or two metals) then this may be mistaken for a chief that violates the rule of tinctures.