diff --git a/lib/dt-core-strpf.c b/lib/dt-core-strpf.c
index 2d460fef..e03f6501 100644
--- a/lib/dt-core-strpf.c
+++ b/lib/dt-core-strpf.c
@@ -277,7 +277,8 @@ __strpdt_card(struct strpdt_s *d, const char *sp, struct dt_spec_s s, char **ep)
 		res = __strpt_card(&d->st, sp, s, ep);
 		goto out_direct;
 
-	case DT_SPFL_N_EPOCH: {
+	case DT_SPFL_N_EPOCH:
+	case DT_SPFL_N_EPOCHNS: {
 		/* read over @ */
 		const char *tp = sp;
 		tp += *tp == '@';
@@ -287,6 +288,10 @@ __strpdt_card(struct strpdt_s *d, const char *sp, struct dt_spec_s s, char **ep)
 		} else {
 			sp = tp;
 		}
+		if (s.spfl == DT_SPFL_N_EPOCHNS) {
+			d->st.ns = d->i % 1000000000;
+			d->i /= 1000000000;
+		}
 		break;
 	}
 
@@ -358,7 +363,8 @@ __strfdt_card(
 		res = __strft_card(buf, bsz, s, &d->st, that.t);
 		break;
 
-	case DT_SPFL_N_EPOCH: {
+	case DT_SPFL_N_EPOCH:
+	case DT_SPFL_N_EPOCHNS: {
 		/* convert to sexy */
 		int64_t sexy = dt_conv_to_sexy(that).sexy;
 		res = snprintf(buf, bsz, "%" PRIi64, sexy);
diff --git a/lib/dt-core.c b/lib/dt-core.c
index afbd18fa..0232e788 100644
--- a/lib/dt-core.c
+++ b/lib/dt-core.c
@@ -702,7 +702,7 @@ dt_strpdt(const char *str, const char *fmt, char **ep)
 
 		if (spec.spfl == DT_SPFL_UNK) {
 			/* must be literal */
-			if (*fp_sav != *sp++) {
+			if (UNLIKELY(*fp_sav != *sp++)) {
 				goto fucked;
 			}
 		} else if (LIKELY(!spec.rom)) {
diff --git a/lib/token.c b/lib/token.c
index e9e06df5..07dd0263 100644
--- a/lib/token.c
+++ b/lib/token.c
@@ -146,6 +146,10 @@ __tok_spec(const char *fp, const char **ep)
 		break;
 	case 's':
 		res.spfl = DT_SPFL_N_EPOCH;
+		if (fp[1U] == '%' && fp[2U] == 'N') {
+			res.spfl = DT_SPFL_N_EPOCHNS;
+			fp += 2U;
+		}
 		break;
 	case 'Z':
 		res.spfl = DT_SPFL_N_ZDIFF;
diff --git a/lib/token.h b/lib/token.h
index caca1dcd..72718fb0 100644
--- a/lib/token.h
+++ b/lib/token.h
@@ -85,6 +85,8 @@ typedef enum {
 	/* date/time specs */
 	/* %s epoch spec, non-standard */
 	DT_SPFL_N_EPOCH,
+	/* %s%N epoch spec, non-standard */
+	DT_SPFL_N_EPOCHNS,
 	/* %Z zone difference */
 	DT_SPFL_N_ZDIFF,
 	DT_SPFL_N_DTLAST = DT_SPFL_N_ZDIFF,
diff --git a/test/Makefile.am b/test/Makefile.am
index 2bf37c84..6fac73b4 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -851,6 +851,7 @@ dt_tests += dtdiff.047.clit
 dt_tests += dtdiff.048.clit
 dt_tests += dtdiff.049.clit
 dt_tests += dtdiff.050.clit
+dt_tests += dtdiff.051.clit
 
 dt_tests += dtround.001.clit
 dt_tests += dtround.002.clit
diff --git a/test/dtdiff.051.clit b/test/dtdiff.051.clit
new file mode 100644
index 00000000..7c8418c1
--- /dev/null
+++ b/test/dtdiff.051.clit
@@ -0,0 +1,7 @@
+#!/usr/bin/clitoris  ## -*- shell-script -*-
+
+$ ddiff -i "%s%N" 1100000000000000000 1000000000000000000
+-100000000s
+$
+
+## dtdiff.051.clit ends here