diff --git a/coverage_test.go b/coverage_test.go
new file mode 100644
index 0000000..43f194e
--- /dev/null
+++ b/coverage_test.go
@@ -0,0 +1,143 @@
+package json
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func intptr(v int) *int {
+	return &v
+}
+
+func int8ptr(v int8) *int8 {
+	return &v
+}
+
+func TestCoverage(t *testing.T) {
+	tests := []struct {
+		name     string
+		expected string
+		data     interface{}
+	}{
+		{
+			name:     "IntHead",
+			expected: `{"a":1}`,
+			data: struct {
+				A int `json:"a"`
+			}{A: 1},
+		},
+		{
+			name:     "IntPtrHead",
+			expected: `{"a":1}`,
+			data: struct {
+				A *int `json:"a"`
+			}{A: intptr(1)},
+		},
+		/*
+			{
+				name:     "IntPtrNilHead",
+				expected: `{"a":null}`,
+				data: struct {
+					A *int `json:"a"`
+				}{A: nil},
+			},
+		*/
+		{
+			name:     "PtrIntHead",
+			expected: `{"a":1}`,
+			data: &struct {
+				A int `json:"a"`
+			}{A: 1},
+		},
+		{
+			name:     "PtrIntPtrHead",
+			expected: `{"a":1}`,
+			data: &struct {
+				A *int `json:"a"`
+			}{A: intptr(1)},
+		},
+		{
+			name:     "IntField",
+			expected: `{"a":1,"b":2}`,
+			data: struct {
+				A int `json:"a"`
+				B int `json:"b"`
+			}{A: 1, B: 2},
+		},
+		{
+			name:     "IntPtrField",
+			expected: `{"a":1,"b":2}`,
+			data: struct {
+				A *int `json:"a"`
+				B *int `json:"b"`
+			}{A: intptr(1), B: intptr(2)},
+		},
+		{
+			name:     "Int8Head",
+			expected: `{"a":1}`,
+			data: struct {
+				A int8 `json:"a"`
+			}{A: 1},
+		},
+		{
+			name:     "Int8PtrHead",
+			expected: `{"a":1}`,
+			data: struct {
+				A *int8 `json:"a"`
+			}{A: int8ptr(1)},
+		},
+		/*
+			{
+				name:     "Int8PtrNilHead",
+				expected: `{"a":null}`,
+				data: struct {
+					A *int8 `json:"a"`
+				}{A: nil},
+			},
+		*/
+		{
+			name:     "PtrInt8Head",
+			expected: `{"a":1}`,
+			data: &struct {
+				A int8 `json:"a"`
+			}{A: 1},
+		},
+		{
+			name:     "PtrInt8PtrHead",
+			expected: `{"a":1}`,
+			data: &struct {
+				A *int8 `json:"a"`
+			}{A: int8ptr(1)},
+		},
+		{
+			name:     "Int8Field",
+			expected: `{"a":1,"b":2}`,
+			data: struct {
+				A int8 `json:"a"`
+				B int8 `json:"b"`
+			}{A: 1, B: 2},
+		},
+		{
+			name:     "Int8PtrField",
+			expected: `{"a":1,"b":2}`,
+			data: struct {
+				A *int8 `json:"a"`
+				B *int8 `json:"b"`
+			}{A: int8ptr(1), B: int8ptr(2)},
+		},
+	}
+	for _, test := range tests {
+		for _, htmlEscape := range []bool{true, false} {
+			var buf bytes.Buffer
+			enc := NewEncoder(&buf)
+			enc.SetEscapeHTML(htmlEscape)
+			if err := enc.Encode(test.data); err != nil {
+				t.Fatalf("%s(htmlEscape:%T): %s: %s", test.name, htmlEscape, test.expected, err)
+			}
+			if strings.TrimRight(buf.String(), "\n") != test.expected {
+				t.Fatalf("%s(htmlEscape:%T): expected %q but got %q", test.name, htmlEscape, test.expected, buf.String())
+			}
+		}
+	}
+}
diff --git a/encode_compile.go b/encode_compile.go
index cb19ac4..0721cec 100644
--- a/encode_compile.go
+++ b/encode_compile.go
@@ -1102,7 +1102,8 @@ func (e *Encoder) compileStruct(ctx *encodeCompileContext, isPtr bool) (*opcode,
 				anonymousFields[k] = append(anonymousFields[k], v...)
 			}
 		}
-		if fieldNum == 1 && valueCode.op == opPtr {
+
+		if fieldNum == 1 && valueCode.op == opPtr && !isPtr {
 			// if field number is one and primitive pointer type,
 			// it should encode as **not** pointer .
 			switch valueCode.next.op {
diff --git a/encode_vm.go b/encode_vm.go
index 4089717..391b826 100644
--- a/encode_vm.go
+++ b/encode_vm.go
@@ -1290,10 +1290,21 @@ func (e *Encoder) run(ctx *encodeRuntimeContext, b []byte, code *opcode) ([]byte
 				b = encodeComma(b)
 				code = code.next
 			}
+		case opStructFieldPtrHeadIntPtr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				b = encodeComma(b)
+				code = code.end.next
+				break
+			}
+			store(ctxptr, code.idx, e.ptrToPtr(p))
+			fallthrough
 		case opStructFieldHeadIntPtr:
 			p := load(ctxptr, code.idx)
 			if p == 0 {
 				b = encodeNull(b)
+				code = code.end.next
 			} else {
 				b = append(b, '{')
 				b = append(b, code.key...)
@@ -1306,10 +1317,21 @@ func (e *Encoder) run(ctx *encodeRuntimeContext, b []byte, code *opcode) ([]byte
 			}
 			b = encodeComma(b)
 			code = code.next
+		case opStructEscapedFieldPtrHeadIntPtr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				b = encodeComma(b)
+				code = code.end.next
+				break
+			}
+			store(ctxptr, code.idx, e.ptrToPtr(p))
+			fallthrough
 		case opStructEscapedFieldHeadIntPtr:
 			p := load(ctxptr, code.idx)
 			if p == 0 {
 				b = encodeNull(b)
+				code = code.end.next
 			} else {
 				b = append(b, '{')
 				b = append(b, code.escapedKey...)
@@ -1319,13 +1341,14 @@ func (e *Encoder) run(ctx *encodeRuntimeContext, b []byte, code *opcode) ([]byte
 				} else {
 					b = appendInt(b, int64(e.ptrToInt(p+code.offset)))
 				}
+				code = code.next
 			}
 			b = encodeComma(b)
-			code = code.next
 		case opStructFieldHeadIntNPtr:
 			p := load(ctxptr, code.idx)
 			if p == 0 {
 				b = encodeNull(b)
+				code = code.end.next
 			} else {
 				b = append(b, '{')
 				b = append(b, code.key...)
@@ -1444,6 +1467,60 @@ func (e *Encoder) run(ctx *encodeRuntimeContext, b []byte, code *opcode) ([]byte
 				b = encodeComma(b)
 				code = code.next
 			}
+		case opStructFieldPtrHeadInt8Ptr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				b = encodeComma(b)
+				code = code.end.next
+				break
+			}
+			store(ctxptr, code.idx, e.ptrToPtr(p))
+			fallthrough
+		case opStructFieldHeadInt8Ptr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				code = code.end.next
+			} else {
+				b = append(b, '{')
+				b = append(b, code.key...)
+				p = e.ptrToPtr(p)
+				if p == 0 {
+					b = encodeNull(b)
+				} else {
+					b = appendInt(b, int64(e.ptrToInt8(p+code.offset)))
+				}
+				code = code.next
+			}
+			b = encodeComma(b)
+		case opStructEscapedFieldPtrHeadInt8Ptr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				b = encodeComma(b)
+				code = code.end.next
+				break
+			}
+			store(ctxptr, code.idx, e.ptrToPtr(p))
+			fallthrough
+		case opStructEscapedFieldHeadInt8Ptr:
+			p := load(ctxptr, code.idx)
+			if p == 0 {
+				b = encodeNull(b)
+				code = code.end.next
+			} else {
+				b = append(b, '{')
+				b = append(b, code.escapedKey...)
+				p = e.ptrToPtr(p)
+				if p == 0 {
+					b = encodeNull(b)
+				} else {
+					b = appendInt(b, int64(e.ptrToInt8(p+code.offset)))
+				}
+				code = code.next
+			}
+			b = encodeComma(b)
 		case opStructFieldPtrAnonymousHeadInt8:
 			store(ctxptr, code.idx, e.ptrToPtr(load(ctxptr, code.idx)))
 			fallthrough