OPENING CHANT [English screenplay p. 109; Japanese screen play pp. 143; dvd 2:05]:

見よ妄執の城の址
魂魄未だ住むごとし
それ熱心の修羅の道
昔も今もかわりなし

Vocabulary:
熱心の修羅の道 nesshin no shura no michi: the path of Ashura who are overcome with passion (bloodlust)

Subtitles:
Look upon the ruins of the castle of delusion
haunted only now by the spirits of those who perished.
A scene of carnage born of consuming desire,
never changing now and throughout eternity.

Screenplay:
Behold the ruins of a castle inhabited by deep-rooted delusion,
perpetually haunted by spirits.
The ruins show the fate of demonic men with treacherous desires.
Life is the same now as in ancient times.

Alternative translation:
Behold, the ruins of a castle of deep-rooted delusion,
haunted even now by spirits/the souls [of men who followed]
this Ashura path of bloodlust;
in the present, as in the past, nothing has changed.

NOTE: The path of warrior demons (shura no michi) is implicitly replacing the path of the samurai (bushidō)

THE FOREST HAG'S CHANT [Japanese screenplay, pp. 146-47; English screenplay p. 112, dvd]:

あさましや あさましや
などて人の世に生をうけ
虫のいのちの細細と
身を苦しむる愚かさよ

Subtitles:
Strange is the world.
Why should men receive life in this world?
Men's lives are as meaningless as the lives of insects.
The terrible folly of such suffering.

English screenplay:
Ah miserable, miserable!
Born into this human world,
Living a transient life like an insect's,
How silly to worry ourselves!

Alternative translation:
How miserable, miserable!
Why do humans, born into this world
their lives as transient as insects,
[experience] the folly of such [needless] suffering!

Compare these lines by the old woman in the Noh play Kurozuka (The Black Mound, AKA Adachigahara):

The hag continues:

あさましや あさましや
花の命は短くて
やがて腐肉となるものを

Subtitles:
A man lives but as briefly as a flower
destined all too soon
to decay into the stink of flesh.

English screenplay:
Ah miserable, miserable!
The life of flowers is too transient,
Only turning to decomposed matter.

Alternative:
Ah miserable, miserable!
[Humans], their life as brief as blossoms,
swiftly turn to putrid, decaying flesh.

それ人間のなりわいは
五慾の炎に身をこがし
五濁の水に身をさらし
業の上は業を積み

Vocabulary:
五慾 goyoku: the Five Desires. Either five desires associated with the five senses, or desire for wealth, sex, food and drink, fame/power, and sleep.
五濁 gojōku: the Five Pollutions/Impurities/Defilements that mark the Age of the Degenerate Dharma (J. mappō, the ten-thousand year period in which Buddha's teaching can no longer be understood or practiced). In Japan mappō was believed to have begun in 1152 or 1158 .The Five Defilements are defined as: 1) Defilement of period (because natural disasters and social chaos arise in this period); 2) Defilement of views (because wrong views arise); 3) Defilement of evil passions (because passions become more intense); 4) Defilement of sentient beings (because people are mentally and physically weak, they reject the Buddha's moral teaching and the law of causality/karma, and therefore suffer greatly); 5) Defilement of life (because man's life-span is shortened)
業 gō: karma. Any act (mental, physical, or verbal) creates effects (karma) that keep us tied to the cycle of reincarnation. Both good and evil acts create karma, however, evil acts will keep us tied to lower realms of reincarnation, such as the Ashura (warrior) Hell.

Subtitles:
Humanity strives all its days
to sear its flesh in the flames of base desire,
exposing itself to the fate's five calamities,
heaping karma upon karma.

English screenplay:
Such being the case, what men do in this world
Burning ourselves with the flames of Five Desires,
Bathing ourselves in the water of the Five Impurities,
Piling up our sins more and more.

Alternative:
So what do humans do?
They burn themselves in the flames of the Five Desires;
they bath themselves in the water of the Five Impurities;
piling up karma upon karma.

迷いの果てに行きつけば
腐肉破れて花と咲き
悪臭かえて香を放つ
面白の人の命
おもしろや　おもしろや

Subtitles:
All that awaits man at the end of his travails
is the stench of rotting flesh,
yet that will blossom into a flower,
its foul odor rendered into sweet perfume.
Oh fascinating the life of man,
Oh fascinating.

English screenplay:
Reaching the last stage of delusion,
Rotten flesh turns to flowers.
Offensive odour becomes perfume,
What a thrilling life for man!
How delightful, delightful!

Alternative:
When one reaches the end of this deluded wandering [i.e. this life],
decaying flesh turns to blossoms,
offensive odor turns to perfume;
How fascinating the life of humans,
how fascinating!

COMPARISON WITH THE INTRODUCTORY LINES OF TALE OF THE HEIKE (Burton Watson translation):

The bells of the Gion monastery in India echo with the warning
that all things are impermanent.
The blossoms of the sala trees teach us through their hues
that what flourishes must fade.
The proud do not prevail for long
but vanish like a spring night's dream.
In time the mighty, too, succumb:
all are dust before the wind.

Notes (taken from Burton Watson and Hiroshi Kitagawa):
Gion monastery: According to Buddhist legend, the Gion monastery, which was built by a rich merchant in a famous garden in India, was the first monastery in the Buddhist order. It is also said that the temple complex included a building known as Impermanence Hall, where dying monks were housed. When they were at their last breath, four silver and four crystal bells were rung to signify the following gatha (Buddhist verse):

All is vanity and evanescence.
That is the law of life and death.
In the complete denial of life and death
Is the bliss of entering Nirvana.

Sala trees: The Nirvana Sutra describes the entrance of the Buddha into Nirvana in detail: at each corner of the Buddha's bed stood a pair of sala (teak) trees. These eight trees bowed down toward the center of the bed and their color changed to the the white of cranes as the Buddha began to pass into Nirvana (i.e. to die).

Later Scene with the Forest Hag

Clip of the scene

When Washizu goes back to the forest to see the hag again, she greets him as the commander of Spiderweb Castle, and says,

"これはこれは,迷いの果てに行きつ枯れた、めでたい、めでたい”
"I see you’ve finally reached the end of your deluded wandering. Congratulations, congratulations."

And after she reassures him that he will not fail until Spiderweb Forest moves to overthrow the castle, and he responds gleefully that this will never happen, she transforms into a phantom Ashura warrior who says:

“Ha, ha, ha, ha. If you are determined on pursing the path of the Ashura, make that path as steeped in evil as you can possibly imagine (omohikiri = without limits).”

Two more phantom warrior figures then encourage Washizu with a similar grammatical structure: “if you are going to pile up a mountain of skulls, make it unimaginably (omohikiri) big”; “if you are going to spill a river of blood, make it flow without limits (omohikiri)."

The question here is whether she is actually encouraging Washizu (which is how he takes it) or not. Generally western critics assume that she is unequivocally telling him to go ahead (and this is a sign of her evil), but is she?

NOH PLAY (Tamura) performed at the banquet by Washizu's senior advisor, which Washizu cuts short:

シテ詞「いかに鬼神もたしかに聞け。 

昔もさるためしあり。 

千方といひし逆臣に仕へし鬼も。 

FINAL CHANT [English screenplay p. 134; Japanese screenplay, 175; but not in the film; simply repeats the opening chant]

寄せ手見えしは
風の葦
鬨の音と聞こえしは
松の風
それ熱心の修羅の道
昔も今もかわりなし

English screenplay:
The attacking force was none other than
the rustling reeds in the breeze.
The war cries were none other than
a breeze in the pine tree.
The ruins show the fate of demonic men with treacherous desires.
Life is the same now as in ancient times.

Alternative:
The attacking force we saw:
reeds in the wind.
The sounds of war we heard:
wind in the pines.
This is the Ashura path of bloodlust:
in the present, as in the past, nothing has changed.  

Note: the first four lines echo a common ending in a second category Warrior Noh play (Shuramono), whereby the reenacted battle performed on stage by the warrior ghost, turns out to have been a dream.

Example from the Warrior Noh Play Yashima

In the final scene, the Minamoto warrior Yoshitsune reenacts the battle of Yashima, which took place at sea:

水や空
空行くも又雲の波の
討ち合ひ刺し違ふる
船車の駆げ引き
浮沈むとせし程に
春の夜の波より明けて
敵と見えし
群れゐるかもめ
鬨の声と聞こえしは
通風なりけり高松の
朝嵐とぞ成りにけり

Sea and sky
mixed in waves of clouds
rising and falling
we grapple boats
stabbing and striking, until
the spring dawn breaks through the waves
and the enemies we saw:
a flock of seagulls;
the sounds of war we heard:
a bay wind sighing through tall pines,
remnants of a morning storm.