3-4 point high approach, keima, tenuki

Keima then tenuki  

In this joseki position (from 3-4 point high approach keima), White may ignore the steady move . In that case Black will continue with a (studied by transposition at 3-4 point high approach, two-space high pincer, tenuki) or b.

Keima  

After , is the normal answer; after which is clearly big.