Kotowaza of the day: Speaking in tongues

Japanese:

二枚の舌を使う

Romanized:

Nimai-no shita-wo tsukau

Meaning of Japanese:

To use two tongues

English equivalents:

Speak with a forked tongue
Have one face to god and another to the devil
Speak out of both sides of one's mouth

Kotowaza of the day: Going to extremes

Japanese:

悪に強ければ善にも強し

Romanized:

Aku-ni tsuyokereba, zen-ni-mo tsuyoshi

Meaning of Japanese:

One capable of great evil is also capable of great good

English equivalents:

The greater the sinner the greater the saint
The greater the man the greater the crime
A good painter can draw a devil as well as an angel

Somewhat related:

There's a fine line between genius and insanity

Kotowaza of the day: Beauty, thy name might also be crow

Japanese:

烏百度洗っても鷺にはならぬ

Romanized:

Karasu hyakudo aratte-mo sagi-ni-wa naranu

Meaning of Japanese:

No matter how much a crow washes, it will never become a (white) heron

English equivalents:

A crow is never the whiter for often washing

Kotowaza of the day: Trust at 100° C

Japanese:

煮え湯を飲まされる

Romanized:

Nieyu-wo nomasareru

Meaning of Japanese:

Be forced to drink boiling water

English equivalents:

To be betrayed horribly
To be badly burned

Kotowaza of the day: Bad Bush!

Japanese:

枯れ木も山の賑わい

Romanized:

Kareki-mo yama-no nigiwai

Meaning of Japanese:

Even a withered bush (tree) livens up mountain scenery somewhat

English equivalents:

A bad bush is better than the open field
Anything is better than nothing

Somewhat related:

Better late than never

In Japanese social situations, where facile deployment of humility is key, this expression is used by some to accept an invitation. Obviously, applying this expression to another person is rude, and may get you challenged to a karaoke smackdown.

Kotowaza of the day: Something to the rumor?

Japanese:

火のない所に煙が立たぬ（立たない）

Romanized:

Hi-no-nai tokoro-ni kemuri-ga tatanu (tatanai)

Meaning of Japanese:

Smoke doesn't rise from a place with no fire

English equivalents:

Where there's smoke, there's fire
There is no smoke without fire

Kotowaza of the day: Take a chance

Japanese:

当たって砕けよ

Romanized:

Atatte kudakeyo

Meaning of Japanese:

Strike out and break (it)*

English equivalents:

Nothing ventured, nothing gained
Go for broke

*Multiple meanings for the japanese atatte (from ataru, 当たる) make a literal translation of this kotowaza problematic. But I think the basic idea is very similar to "go for broke." You'll never know unless you try.

Kotowaza of the day: rational submission

Japanese:

長い物には巻かれろ

Romanized:

Nagai mono-ni-wa makarero

Meaning of Japanese:

If the thing is long, just let yourself be enveloped/wrapped up in it
Yield to a force more powerful than you

English equivalents:

If you can't beat 'em, join 'em
You can't fight city hall
Kings have long arms

Kotowaza of the day: A forgotten virtue

Japanese:

武士に二言はない

Romanized:

Bushi-ni ni gon-wa nai

Meaning of Japanese:

A samurai will never go back on his word

English equivalents:

To give one's word of honor
Promise is debt
A man's word is (as good as) his bond

Kotowaza of the day: The birth of JIT

Japanese:

渡りに舟

Romanized:

Watari-ni fune

Meaning of Japanese:

A boat for the crossing

English equivalents:

(for something to come with) Great timing
How convenient!

Kotowaza of the day: Man's best friend?

Japanese:

飼い犬に手を噛まれる

Romanized:

Kaiinu-ni te-wo kamareru

Meaning of Japanese:

To get bit by one's own dog
To get backstabbed/be betrayed

English equivalents:

Man may cause his own dog to bite him
Caress your dog and he'll spoil your clothes

Related:

Don't bite the hand that feeds you

Kotowaza of the day: Hypocritic Oath

Japanese:

医者の不養生

Romanized:

Isha-no fuyoujou

Meaning of Japanese:

A doctor disobeying doctor's orders

English equivalents:

It is a good physician who follows his own advice

Related:

Do as I say, not as I do
Physician, heal thyself!
Few lawyers die well, few physicians live well